Atomic Structure and the Periodic Table

Lesson 2August 12 & 13, 2013

BoonChemistry

Mystery Elements! Use your periodic table and the clues below to determine the identity of 3 mystery elements. Write your answers on your white board.

1. This element, with a mass number of 207, is poisonous.

2. This element, made of atoms with 78 electrons in the neutral state, is a very expensive metal.

3. This element, made of atoms with 16 protons, is a gas that smells like rotten eggs.

Catalyst

If you finish early, begin correcting your lab.

Atomic Symbol: PbAtomic Number: 82Mass Number: 207.2

207Pb

1. Answer: Lead

Atomic Symbol: PtAtomic Number: 78Mass Number: 195.08

195Pt

2. Answer: Platinum

Atomic Symbol: SAtomic Number: 16Mass Number: 32.07

32S

3. Answer: Sulfur

When given data and a periodic table, students relate the numbers of subatomic particles in an atom and the periodic table by drawing models of atoms and distinguishing between diagrams of different isotopes and ions.

Objective

More simply: I can identify an element based on its atomic structure and I can draw a model of an atom of a specific element using information found on the periodic table.

Writing & Reading Nuclear Symbols

284Be

Format on the Periodic Table

Format on a worksheet or lab report

Atomic Number

Mass Number

Ion with 2+ charge

Write the nuclear symbol for…1. Calcium-41 (mass number = 41)2. Magnesium ion with 2+ charge3. Argon-404. Tungsten-1845. A gold atom with 117 neutrons6. A lithium atom with 2 electrons

White Board Practice

Sometimes, atoms of the same element have different numbers of neutrons. Atoms of the same element with different numbers of neutrons are called isotopes.

Question 1 Three isotopes of magnesium are

◦ Magnesium – 24 (24Mg)◦ Magnesium – 25 (25Mg)◦ Magnesium – 23 (23Mg)

Complete the Chart:

Hint! Mass number = protons + neutrons

Isotope Protons Neutrons Electrons

Mg – 24

Mg – 25

Mg - 23

Question 2 Three isotopes of uranium are

◦ Uranium – 235 (235U)◦ Uranium – 238 (238U)◦ Uranium – 236 (236U)

Complete the Chart:

Hint! Mass number = protons + neutrons

Isotope Protons Neutrons Electrons

U – 235

U – 238

U - 236

• Ions are atoms with a net charge. The ion is charged because there are an unequal number of protons and electrons.

• The charge is shown on the right side of the symbol:

• Ex: Mg with 12 protons and 10 electrons Mg2+

Positive or Negative? Positively charged ions have more protons

than electrons◦ Ex: Ca2+ (calcium ion) has 20 protons and 18

electrons 20 – 18 = +2

Negatively charged ions have more electrons than protons◦ Ex: Br- (bromine ion) has 35 protons and 36 electrons

35 – 36 = -1

Name that ion!

Sample: ◦ 19 protons, 20 neutrons, 18 electrons

Answer: K1+ +19 p + (-18 e) = +1

Now you try: 13 protons, 14 neutrons, 10 electrons 1 proton and no electrons 53 protons, 73 neutrons, 54 electrons 16 protons, 16 neutrons, 18 electrons 4 protons, 5 neutrons, 2 electrons

“groups” are columns “periods” are rows

Note on the Periodic Table

Just like you and your family share similarities… So do elements!

• 3 main groups1. Metals2. Non-metals3. Semi-metals

1. METALS

LOCATION on the Periodic Table: To the left, to the left…

2. NON-METALS

LOCATION on the Periodic Table: To the right, and with the exception of Hydrogen!

LOCATION on the Periodic Table: the Semi-metal “Staircase”

What are the semi-metals?B, Si, Ge, As, Sb, Te

3. SEMI-METALS (Metalloids)

Please color-code your periodic tables.

• The majority of elements are…

METALS

B

Si

Ge As

Sb Te

Things you should know about periodic table groups:

1. Where is the group located on the periodic table? 2. What groups (columns) and periods (rows) are

included?3. What are some of the elements included?4. Are you part of the metals, semi-metals

(metalloids), or non-metals?5. How many valence electrons does each element

possess?6. Please present two more facts or examples from

the textbook. (Pages 125-129 in textbook).

Study Jam - atoms: http://studyjams.scholastic.com/studyjams/jams/science/matter/atoms.htm

Study Jam - Periodic table: http://studyjams.scholastic.com/studyjams/jams/science/matter/periodic-table.htm

Just How Small is an Atom? http://www.youtube.com/watch?v=yQP4UJhNn0I

Solving the puzzle of the periodic table http://www.youtube.com/watch?v=O-48znAg7VE&list=PLJicmE8fK0EjGmPGeh_WDu69qAsN-iHVA

The genius of Mendeleev’s Periodic table http://www.youtube.com/watch?v=fPnwBITSmgU&list=PLJicmE8fK0EjGmPGeh_WDu69qAsN-iHVA

Video Review

Halogens: http://www.youtube.com/watch?v=u2ogMUDBaf4

Alkali Metals: http://www.youtube.com/watch?v=uixxJtJPVXk

Alkaline Earth Metals: http://www.youtube.com/watch?v=B2ZPrg9IVEo

Videos – Elements

Detailed Notes on Periodic Table Groups

Check these notes against your periodic table graphic organizer.

• Within the 3 major groupings of elements (metals, semi-metals, non-metals), there are more SPECIFIC groups that share properties.

• The elements share properties because they have the same number of VALENCE ELECTRONS.

• VALENCE electrons: electrons that

are in the OUTERMOST shell of an

atom. They are the electrons

available for CHEMICAL BONDING.

Group 1: The Alkali Metals

• Have ONE valence electron.• VERY REACTIVE• Therefore, not found alone in

nature.• What are the alkali metals?

– Li, Na, K, Rb, Cs, Fr

Group 2: The Alkaline Earth Metals

• Have TWO valence electrons.

• VERY REACTIVE• Usually not alone

uncombined in nature.• What are the Alkaline

Earth Metals? Be, Mg, Ca, Sr, Ba, Ra

Groups 3-12: Transition metals

• Properties vary.• Some found alone in nature: Gold,

Silver, Platinum, Copper, etc.

Group 17: Halogens

• Have SEVEN valence electrons.• Most REACTIVE non-metals.• What are the Halogens? F, Cl, Br, I, At

Group 18: The Noble Gases

• Have EIGHT valence electrons.• They are very NON-REACTIVE (Like to

exist alone).• What are the Noble Gases? He, Ne,

Ar, Kr, Xe, Rn

Lanthanides and Actinides

• The lathanides are actinides are transition metals.

• They are part of period 6 and 7, however they are placed below the table so that it fits on one page.

• Locate the atomic numbers of the lanthanides and actinides. You will notice that they fill in the gaps in atomic numbers between Ba & Hf and Ra & Rf.

Transuranium Elements

• These are elements listed after Uranium (92) on the periodic table.

• Transuranium elements were synthesized and identified in laboratory experiments through the use of nuclear accelerators.

• They are not naturally found on earth.

1. METALS• Physical properties

– Solids at room temperature (250C)– Luster (shininess)– Good conductors of heat and electricity– High density (Heavy for its size!)– High melting point– Ductile (thin wire)– Malleable (thin sheets)

QuickTime™ and a decompressor

are needed to see this picture.

QuickTime™ and a decompressor

are needed to see this picture.

1. METALS

• Chemical properties– Tend to LOSE electrons when bonding

• form positive ions – ex. K+, Al3+

– Sometimes corrode (disappear slowly by chemical damage) or rust (reacts with oxygen)

2. NON-METALS

• Physical properties (tend to be the opposite of metals)– Mostly gases at room temperature– No luster (dull)– Non-conductors of heat and electricity– Low density– Low melting point– Brittle (breaks easily) QuickTime™ and a

decompressorare needed to see this picture.

2. NON-METALS

• Chemical properties– Tend to GAIN electrons when bonding

3. SEMI-METALS (Metalloids)

• Tend to have both metallic and non-metallic physical and chemical properties.

• For example, a semi-metal may be shiny like a metal, but cannot conduct electricity.

http://www.rsc.org/periodic-table/

http://www.chemicalelements.com/index.html

http://www.webelements.com/pictures.html

Periodic Table Websites