chem up day 2 - daytona state college · pdf filethe academic support center @ daytona state...

The Academic Support Center @ Daytona State College (Chem-Up 2, of 114)

D A Y 2 - 2 0 1 3

CHEM-UP!


Chapter 4 Lecture

Basic Chemistry Fourth Edition

Chem Up! An Introduction to Basic Chemistry Concepts

Day 2

As you come in:

1. Sign in.

2. Write your name on a “raffle ticket” to leave at the

front desk.


Welcome!

Please introduce yourself to your

neighbors. Some activities will

require working in groups of two to

three.


IceBreaker

Time to take a

short quiz.


Quiz

1. How do you get a giraffe into a refrigerator?

2. How do you get an elephant into a refrigerator?

3. The Lion King is having a meeting and has invited every animal on Earth to attend. What animal does not show up?

4. There is a lake normally full of angry crocodiles and you need to get to the other side. How do you do it?


Quiz Solutions

1. How do you get a giraffe into a refrigerator?

• You just push it in.

2. How do you get an elephant into a refrigerator?

• First you have to pull out the giraffe in order to push in the elephant.

3. The Lion King is having a meeting and has invited every animal on Earth to attend. What animal does not show up?

• The elephant, because it is in the refrigerator.

4. There is a lake normally full of angry crocodiles and you need to get to the other side. How do you do it? • Just swim across. All of the animals but the elephant are at the meeting.


AGENDA FOR DAY 2

Atoms & Elements

•Elements & Symbols

•The Periodic Table

•Atoms

•Atomic # and Mass #

•Isotopes

•Valence Electrons

•Ions


Atoms and Elements

1)Elements and Symbols

Learning Goal Given the name

of an element, write its correct

symbol; from the symbol, write

the correct name.

© 2014 Pearson Education, Inc.



Elements are pure substances from which everything else is built.

Over the centuries, elements have been named for

• planets

• mythological figures

• minerals

• geographic locations

• famous people

Elements



Sources of Element Names



Chemical Symbols are one or two letter abbreviations for an element’s name.

When chemical symbols contain two letters, the second letter is NOT capitalized.

• Co is the chemical symbol for cobalt.

• CO specifies there are two elements present, carbon and oxygen.

Chemical Symbols



Aluminum, Al Silver, Ag

Gold, Au Sulfur, S

Names and Symbols of Elements



Learning the names and symbols for elements

will greatly help your learning of chemistry.

Names and Symbols of Elements

Name of

Element

Element

Symbol

Name of

Element

Element

Symbol

Aluminum Al Hydrogen H

Barium Ba Iodine I

Carbon C Nitrogen N

Calcium Ca Oxygen O

Chlorine Cl Phosphorus P



The chemical symbol for carbon is C. Carbon

atoms can arrange themselves in different ways

to make different substances.

• Graphite contains carbon atoms connected to

each other in planes of hexagonal rings. We

use graphite for lubricants and in pencils.

Chemistry Link to Industry



• Carbon atoms are also arranged in a rigid

structure forming diamonds. Diamonds are

transparent and much harder than graphite.

Chemistry Link to Industry



Select the correct symbol for each element:

1. calcium (a) C (b) Ca (c) CA

2. sulfur (a) S (b) Sl (c) Su

3. iron (a) Ir (b) FE (c) Fe

4. sodium (a) S (b) So (c) Na

5. magnesium (a) Mg (b) Mn (c) Ma

Learning Check



Select the correct symbol for each element:

1. calcium (b) Ca

2. sulfur (a) S

3. iron (c) Fe

4. sodium (c) Na

5. magnesium (a) Mg

Solution



Select the correct element name for each symbol:

1. N (a) neon (b) nitrogen

2. P (a) potassium (b) phosphorus

3. Ag (a) silver (b) gold

4. K (a) krypton (b) potassium

5. F (a) fluorine (b) fempto

Learning Check



Select the correct element name for each symbol:

1. N (b) nitrogen

2. P (b) phosphorus

3. Ag (a) silver

4. K (b) potassium

5. F (a) fluorine

Solution



• Compounds are composed of two or more elements chemically combined in a definite ratio.

• Mixtures are two or more substances which are physically mixed but not chemically combined.

• Homogeneous mixtures:

• Have uniform composition

• Different components are not visible

• Liquid homogeneous mixtures are called solutions

• Heterogeneous mixtures:

• Do not have uniform composition

• Different components are visible

Compounds and Mixtures


Atoms and Elements

2) The Periodic Table

Learning Goal Use the periodic table

to identify the group and the period of

an element; identify the element as

a metal, a nonmetal, or a metalloid.



In 1872, Dmitri Mendeleev

• created the periodic table

• arranged elements by increasing atomic mass

• arranged elements into groups with similar properties


The Periodic Table


Write as much relevant information on your periodic table as possible. Mark it up! Make it pretty! Have fun with it!

•Annotate / Add side notes

•Color is your friend

•Organize information


Useful Study Technique(s)


The Periodic Table


Periods and Groups

On the periodic table

• elements are arranged according to similar

properties in vertical columns called groups

• periods are horizontal rows of elements

Period 1 contains two elements: H and He

Periods 2 and 3 each contain eight elements:

Period 2 – Li, Be, B, C, N, O, F, He

Period 3 – Na, Mg, Al, Si, P, S, Cl, Ar


Periods and Groups


Group Numbers, written at the top of each

vertical column, are written two ways:

• The letter A is used for the representative

elements 1A to 8A and the letter B for the

transition elements.

• The numbers 1–18 are used for the columns

from left to right.

Group Numbers


Group Numbers


Representative Elements

Group 1A (1) Group 7A (17)

Alkali metals Halogens

Lithium,

sodium, and

potassium

are some

alkali

metals from

Group 1A.

Chlorine,

bromine, and

iodine are

halogens from

Group 7A.


Metals, Nonmetals, and Metalloids

The heavy zigzag line on the periodic table

separates the metals from nonmetals.

Metalloids border the zigzag line.



Most metals are shiny solids, such as copper

(Cu), gold (Au), and silver (Ag).

Metals are

• ductile, can be shaped into wires

• malleable, can be hammered into a flat sheet

• good conductors of electricity

• melted at much higher temperatures than

nonmetals

• solids at room temperature, except for

mercury (Hg)


Except for aluminum (Al), the elements along

the zigzag line are metalloids. Metalloids

• include B, Si, Ge, As, Sb, Te, Po, and At

• exhibit some properties typical of metals and

some typical of nonmetals

• are better conductors of heat and electricity

than nonmetals, but not as good as metals

• are semiconductors because they can be

modified to function as conductors or insulators



Nonmetals include elements such as hydrogen (H),

carbon (C), nitrogen (N), oxygen (O), chlorine

(Cl), and sulfur (S).

Nonmetals

• not especially shiny, malleable, or ductile, and

are often poor conductors

of heat and electricity

• typically have low melting

points and low densities



Study Check

• Compare your

annotated periodic

table with the side

model.

• Discuss your

observations with a

peer.

How can you apply this technique to other courses?


Chemistry Link to Health

• Only 23 elements are essential for the well-being

and survival of the human body.

• Only four elements, oxygen (O), carbon (C),

hydrogen (H) and nitrogen (N) make up 96 % of

our body mass.

• The macrominerals Ca, P, K, Cl, S, Na, and Mg

are involved in the formation of bones and teeth,

and the maintenance of essential body functions.


Chemistry Link to Health


Learning Check

Match the elements to the description:

1. Metals in Group 4A (14)

(a) Sn, Pb (b) C, Si (c) C, Si, Ge, Sn

2. Nonmetals in Group 5A (15)

(a) As, Sb, Bi (b) N, P (c) N, P, As, Sb

3. Metalloids in Group 4A (14)

(a) C, Si, Ge (b) Si, Ge (c) Si, Ge, Sn, Pb


Solution

Match the elements to the description:

1. Metals in Group 4A (14)

(a) Sn, Pb

2. Nonmetals in Group 5A (15)

(b) N, P

3. Metalloids in Group 4A (14)

(b) Si, Ge


Time for Lesson 4

Introduction to Chemistry


Atoms and Elements 3) The Atom

Learning Goal Describe the electrical

charge and location in an atom for a

proton, a neutron and an electron.



All elements listed on the periodic table are made up of atoms. An atom is the smallest particle of an element.


The Atom


The idea of atoms did not become scientific theory until 1808.

John Dalton (1766–1844) developed an atomic theory proposing that atoms were responsible for the combinations of elements in compounds.

Dalton's Atomic Theory



1. All matter is made up of tiny particles

called atoms.

2. All atoms of a given element are identical to

one another and different from atoms of other

elements.


3. Atoms of two or more different elements

combine to form compounds. A particular

compound is always made up of the same

kinds of atoms and the same number of each

kind of atom.

4. A chemical reaction involves the

rearrangement, separation, or combination of

atoms. Atoms are never created or destroyed

in a chemical reaction.



Atoms are

• the building blocks of everything around us

• too small to see with the naked eye

A small sample of nickel contains many, many nickel atoms.

Atoms


By the end of the 1880s,

• experiments with electricity showed that atoms

were composed of tiny particles, called

subatomic particles including protons,

neutrons, and electrons

• it was shown that some subatomic particles in

an atom have charge

Subatomic Particles in an Atom


Electrical charges can be positive or negative.

• two positive charges repel each other

• two negative charges repel each other

• unlike charges attract each other

Electrical Charges in an Atom


In 1911, Ernest Rutherford worked with

J. J. Thomson on experiments in which they

discovered that atoms contained

• a small region in the center with positive

charge called the nucleus

• a region of space around the center of the

atoms occupied by electrons

The Structure of an Atom


The positively charged particles are called protons,

and the negatively charged particles are called

electrons.

If an atom were the size of a football stadium, the

size of the nucleus would be the size of a golf ball

in the center of the field.



In 1932, James Chadwick discovered that the

nucleus of the atom also contained neutral particles

called neutrons.



54

Creating funny stories or jokes is a good way to

remember information!

http://www.google.com/imgres?imgurl&imgrefurl=http%3A%2F%2Fwww.tumblr.com%2Ftagged%2Fchemistry%2520jokes%3Flanguage%3Dnl_NL&h=0&w=0&sz=1&tbnid=yPKRZcDzQqnazM&tbnh=194&tbnw=260&prev=%2Fsearch%3Fq%3Dchemistry%2Bjokes%26tbm%3Disch%26tbo%3Du&zoom=1&q=chemistry%20jokes&docid=d9SRU2F1aD7uzM&hl=en&ei=-9b2UY-JLYrG9gTQn4CACg&ved=0CAEQsCU



In an atom, the protons

and neutrons that make

up almost all the mass of

the atom are packed into

the tiny volume of the

nucleus. The rapidly

moving electrons

(negative charge)

surround the nucleus and

account for the large

volume of the atom.


Structure of an Atom Video

http://youtu.be/TBrJt-5LHgQ





Mass of the Atom

• The mass of the atom is due to the protons and

neutrons in the nucleus. Electrons have a much

smaller mass.

• Chemists use a unit called atomic mass unit

(amu), defined as one-twelfth of the mass of

the carbon atom with 6 protons and 6 neutrons.

• The mass of all elements in the periodic table is

compared to the mass of this carbon atom.


On the amu scale, the mass of a proton and a

neutron have a mass of about 1 amu.

Mass of an Atom


The atomic mass of an element is

• listed below the symbol of each element on

the periodic table

• calculated based on the weighted average

of all naturally occurring isotopes

• based on its comparison

to the mass of 12C

• not the same as

the mass number

Atomic Mass

11

Na

22.99 Atomic Mass


Is each of the following statements true or false?

A. The mass of an electron is greater than the mass

of a proton.

B. Protons have a positive charge, and electrons

have a negative charge.

C. The nucleus of an atom contains only the

protons and neutrons.

Learning Check


Is each of the following statements true or false?

A. The mass of an electron is greater than the mass

of a proton. False

B. Protons have a positive charge, and electrons

have a negative charge. True

C. The nucleus of an atom contains only the

protons and neutrons. True

Solution


Atoms and Elements

4) Atomic Number and Mass Number

Learning Goal Given the atomic

number and the mass number of an

atom, state the number of protons,

neutrons, and electrons.



The atomic number

• is specific for each element and the same for

all atoms of that element

• is equal to the number of protons in an atom

• appears above the symbol of an element

Atomic Number

Chemical Symbol


Atomic Number

11

Na


• Hydrogen has atomic number 1; every H atom

has 1 proton.

• Carbon has atomic number 6; every C atom

has 6 protons.

• Copper has atomic number 29; every Cu atom

has 29 protons.

• Gold has atomic number 79; every Au atom

has 79 protons.

Atomic Numbers and Protons


Atomic Models


State the number of protons in each atom.

1. A nitrogen atom

(a) 5 protons (b) 7 protons (c) 14 protons

2. A sulfur atom


3. A barium atom


Learning Check


State the number of protons in each atom.

1. A nitrogen atom (b) 7 protons

2. A sulfur atom (b) 16 protons

3. A barium atom (c) 56 protons

Solution


An atom of any element

• is electrically neutral; it has a net charge of zero

• has an equal number of protons and electrons

A neutral atom of calcium, atomic number 20,

contains 20 protons and 20 electrons. It has zero

net charge.

Atoms Are Neutral


The mass number

• represents the number of particles in the

nucleus

• is equal to the

number of protons + number of neutrons

• does not appear on the periodic table because it

applies to a single atom only

Mass Numbers


We calculate the number of neutrons in an atom

from its mass number and atomic number:

mass – atomic = number number number neutrons

Potassium has a mass number of 39 and an

atomic number of 19. To find the number of

neutrons, subtract the atomic number from its

mass number. 39 (mass number) – 19( atomic number) = 20 neutrons

Calculate Number of Neutrons


8

Composition of Elements


An atom of zinc has a mass number of 65.

1. How many protons are in the nucleus?

(a) 30 (b) 35 (c) 65

2. How many neutrons are in the nucleus?

(a) 30 (b) 35 (c) 65

3. What is the mass number of a zinc atom

that has 37 neutrons?

(a) 37 (b) 65 (c) 67

Learning Check


An atom of zinc has a mass number of 65.

1. How many protons are in the nucleus?

(a) 30

2. How many neutrons are in the nucleus?

(b) 35

3. What is the mass number of a zinc atom

that has 37 neutrons?

(c) 67

Solution


An atom has 14 protons and 20 neutrons.

1. Its atomic number is

(a) 14 (b) 16 (c) 34

2. Its mass number is

(a) 14 (b) 16 (c) 34

3. The element is

(a) Si (b) Ca (c) Se

Learning Check


An atom has 14 protons and 20 neutrons.

1. Its atomic number is

(a) 14

2. Its mass number is

(c) 34

3. The element is

(a) Si

Solution


Useful Study Technique

• Work in groups to create flash cards that

will help you distinguish the differences

between atomic mass, mass number and

atomic structure.

• Think about using colors, abbreviations,

etc. so that you can visualize the flash

cards when recalling information.

76


Time for Lesson 5

Atomic Theory - The Basics


Atoms and Elements

5) Isotopes and Atomic Mass

Learning Goal Give the number of protons, electrons, and neutrons in one or more of the isotopes of an element; understand the atomic mass of an element,.



Isotopes

• are atoms of the same element that have

different mass numbers

• have the same number of protons, but different

numbers of neutrons

• most elements have two or more isotopes that

contribute to the atomic mass of that element.


Isotopes


An atomic (nuclear) symbol

• represents a particular isotope of an element

• gives the mass number in the upper left corner

and the atomic number in the lower left corner

mass number

Atomic Symbols

12

24 MgChemical Symbol

atomic

number


Atomic Symbols, Subatomic Particles

The atomic symbol indicates the number of

protons, neutrons and, electrons in a specific

isotope of an element.

8 protons 15 protons 30 protons

8 neutrons 16 neutrons 35 neutrons

8 electrons 15 electrons 30 electrons

15

31P

8

16O

30

65 Zn


1. Which of the following pairs are isotopes of

the same element?

2. In which of the following pairs do both atoms have 8 neutrons?

A.

B.

C.

Learning Check

8

15 X and 7

15X

6

12 X and 6

14X

7

15 X and 8

16X


1. Which of the following pairs are isotopes of

the same element?

B.

Each has 6 protons and, the element is carbon.

Different mass numbers indicate that each

species has a different number of neutrons.

These are isotopes.

Solution

6

12 X and 6

14X


Solution

2. In which of the following pairs do both atoms have 8 neutrons?

C.

The number of neutrons is calculated.

mass number – atomic number = number neutrons

15 (mass number) – 7 (atomic number)

= 8 neutrons

mass number – atomic number = number neutrons

16 (mass number) – 8 (atomic number)

= 8 neutrons

7

15 X and 8

16X

7

15 X

8

16 X


Concept Map


Atoms and Elements

6) Valance Electrons

Learning Goal Understand the definition of valance electrons and electron dot structures.


Valence Electrons

The valence electrons,

•are related to the group number of the element

•determine the chemical properties of an element

Example: Phosphorus has five valence electrons.

P Group 5A(15)


Group Numbers and Valence Electrons

All the elements in a group have the same

number of valence electrons.

Elements in Group 2A (2) have two (2) valence

electrons.

Be

Mg

Ca

Sr


Learning Check

State the number of valence electrons for each:

1. O (a) 4 (b) 6 (c) 8

2. Al (a) 13 (b) 3 (c) 1

3. Cl (a) 2 (b) 5 (c) 7

4. Tin (a) 2 (b) 4 (c) 14

5. Group 6A (16)

(a) 2 (b) 4 (c) 6


Solution

State the number of valence electrons for each:

1. O (b) 6

2. Al (b) 3

3. Cl (c) 7

4. Tin (b) 4

5. Group 6A (16) (c) 6


Electron-Dot Symbols

An electron-dot symbol

• indicates the number of valence electrons as

dots around the symbol of the element

• for Mg shows two valence electrons placed as

single dots on the sides of the symbol Mg

Mg

Electron-Dot Symbols for Magnesium


Electron-Dot Symbols


Summary, Periodic Table Trends


Ionic and Molecular Compounds

7) Ions: Transfer of Electrons

Learning Goal Write the

symbols for the simple ions of

the representative elements.


Compounds

Most elements except for noble gases are found in nature combined with other elements in compounds.

Compounds form when electrons are transferred or shared to give a stable electron configuration to both atoms.


Compounds

Atoms lose, gain, or share electrons in the form of an ionic bond or covalent bond to obtain an octet.

• Ionic bonds are formed when the valence electrons of a metal are transferred to atoms of nonmetals.

• Covalent bonds are formed when atoms of nonmetals share their valence electrons.


Ionic and Molecular Compounds


Positive Ions: Loss of Electrons

Ions, which have electrical charges, form when atoms lose or gain electrons to form a stable electron configuration.

• Because ionization energies of metals in Group 1A (1), 2A (2), and 3A (13) are low, metal atoms lose their valence electrons, forming ions with a positive charge.



A sodium atom (Na) will lose its valence electron to form a sodium ion (Na+).

Positively charged ions of metals are called cations.



Magnesium, a metal in Group 2A (2), obtains a stable electron configuration by losing two valence electrons, forming an ion with a 2+ charge.


Negative Ions: Gain of Electrons

The ionization energy of a nonmetal atom in Groups 5A (15), 6A (16), and 7A (17) is high. Rather than lose electrons to form ions, a nonmetal atom will gain one or more electrons to obtain a stable electron configuration.


Negative Ions: Gain of Electrons

An atom of chlorine with seven valence electrons gains one electron to form an octet. Because it now has 18 electrons and not 17 electrons, it becomes a chloride ion (Cl−) with a charge of 1−.

Negatively charged ions of nonmetals are called anions.


Formula and Names of Some Common Ions


Learning Check

Select the correct answer for aluminum.

1. The electron change to obtain an octet is _____.

(a) loss of 3 e− (b) gain of 3 e− (c) gain of 5 e −

2. The charge of the aluminum ion is _____.

(a) 3− (b) 5− (c) 3+

3. The symbol for the aluminum ion is _____.

(a) Al3+ (b) Al3– (c) Al+


Solution

Select the correct answer for aluminum.

1. The electron change to obtain an octet is _____.

(a) loss of 3 e−

2. The charge of the aluminum ion is _____.

(c) 3+

3. The symbol for the aluminum ion is _____.

(a) Al3+


Ionic Charges from Group Numbers

We can use group numbers of representative

elements in the periodic

table to determine their

charges.

Group

Number

Ion

Charge

Group 1A (1) 1+

Group 2A (2) 2+

Group 3A (13) 3+

Group 5A (15) 3−

Group 6A (16) 2−

Group 7A (17) 1−


Common Ions and Their Nearest

Noble Gases

Atoms lose or gain electrons to become like their

nearest noble gas.


Learning Check

Select the correct answer for sulfur.

1. The group number for sulfur is _____.

2. The number of valence electrons in sulfur

is ____.

3. The change in electrons for an octet requires a

(a) loss of 2 e− (b) gain of 2 e− (c) gain of 4 e−

4. The ionic charge of a sulfide ion is _____.

(a) 2+ (b) 2− (c) 4−


Solution

Select the correct answer for sulfur.

1. The group number for sulfur is 6A (16).

2. The number of valence electrons in sulfur

is six.

3. The change in electrons for an octet requires a

(b) gain of 2 e−

4. The ionic charge of a sulfide ion is _____.

(b) 2−


Chemistry Link to Health, Ions

Several ions in body fluids have important

physiological and metabolic functions.


Time for Lesson 6

Atoms and Ions


SNEAK PEEK…AGENDA FOR DAY 3

Bonds & Intermolecular Forces

•Molecular Bonding

•Electronegativity & Polarity

•Intermolecular Bonding

•Solvency

•Attractive Forces


Compiled by J. Picione (Chemistry Faculty) D. Leonard, R. Wendt, J. Brown, E. Scott, and A. Kandefer (Learning Specialists) The Academic Support Center @ Daytona State College http://www.daytonastate.edu/asc/ascsciencehandouts.html

Questions

http://www.daytonastate.edu/asc/ascsciencehandouts.html

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