Ch 6 - The Periodic Table and Periodic Law

6.1 Development of the Modern Periodic TableReview Vocabulary

atomic number - the number of protons in an atomMain Idea - The periodic table evolved over time as scientists discovered more useful ways to compare and organize the elements.New Vocabulary

periodic lawgroupperiodrepresentative elementstransition elementsmetalalkali metalsalkaline earth metals

Organizing the Elements A few elements, such as ____________ and _____________, have been known for thousands of

years - since ancient times Yet, only about _____ had been identified by the year 1700. As more were discovered, chemists realized they needed a way to______________ the

elements. Chemists used the _______________ of elements to sort them into _______________. In the 1700s, _______________ compiled a list of all the known elements of the time.

Mendeleev’s Periodic Table By the mid-1800s, about______ elements were known to exist

o Dmitri ___________________ – a Russian chemist and teachero Arranged elements in order of increasing _______________________.o Thus, the first “_____________ Table”

He left ___________ for yet undiscovered elements When they were discovered, he had made__________ predictions

transition metalinner transition metallanthanide seriesactinide seriesnonmetalshalogennoble gasmetalloid

But, there were ________________ .o Co and Ni; Ar and K; Te and Io The_______________ were not correct when arranged by _________________.

Continued Development of the Periodic Table The 1800s brought large amounts of information and scientists needed a way to organize

knowledge about elements. John _____________– English Chemist

o proposed an arrangement where elements were ordered by increasing atomic mass.

o noticed when the elements were arranged by increasing atomic mass, their properties repeated every ____________element.

A Better arrangement The modern periodic table was arranged in 1913. Henry ______________– British physicist

o arranged elements according to increasing _________________o The arrangement used ____________.

The symbol, atomic number & __________ are basic items included

Development of the Periodic Table Summary _____________and ___________________ both demonstrated a connection between atomic

mass and elemental properties. ________________rearranged the table by increasing atomic number, and resulted in a clear

periodic pattern. Periodic _______________of chemical and physical ________________ of the elements when

they are arranged by increasing atomic number is called _____________________. The modern periodic table contains boxes which contain the element's name, symbol, atomic

number, and atomic mass.

6.1 The Modern Periodic Table When elements are arranged in order of _____________________atomic number, there is a

periodic repetition of their physical and chemical properties. Columns of elements are called______________.

o Similar physical and chemical _______________.o Identified by number (1-18) or Roman number and letter (IA, IIA…)

Rows of elements are called _______________. Elements in groups 1,2, and 13-18 possess a wide variety of chemical and physical properties

and are called the ________________________________. Elements in groups 3-12 are known as the ______________________________.

Areas of the periodic table _______________________________________

o Groups 1A through 8A (or 1, 2, 13-18)o Display ____________________of properties, thus are good “__________________” of

the types of chemical __________________. o Some are metals, or nonmetals, or metalloids; some are solid, others are gases or liquids

Group “___” Elementso All have _______________ properties

Three classes of elements: 1) ______________________2) ______________________3) ______________________

Metals o electrical conductors, have luster, ductile, malleable

Nonmetals :o generally brittle and non-lustrous, poor conductors of heat and electricityo Some nonmetals are gases (O, N, Cl); some are brittle solids (S); one is a fuming dark red

liquid (Br)

Notice the heavy, stair-step line?

Metalloids :o border the line-2 sideso Properties are “_______________” between metals and nonmetalso They have properties of __________metals and nonmetals

6.1 More on Metals _____________ are elements that are generally shiny when smooth and clean, solid at room

temperature, and good conductors of heat and electricity. __________________________ are all the elements in group 1 _____________hydrogen, and

are very reactive.o Form a “____________” (or alkali) when _______________ with water

______________________________________ are in group 2, and are also highly reactive.o Also form_____________ with water; o do not dissolve well

The transition elements are divided into transition metals and inner transition metals.

____________________________ :o All are hard, good conductors, malleable, ductile, high melting and boiling points (except

_________________of course), etc.o Examples are gold, copper, silver

_________________________________ : o The two sets of inner transition metals are called the lanthanide series and actinide

series and are located at the bottom of the periodic table.o ______ Group designationso Formerly called “_____________________” elements, but this is not true because some

are very abundant

6.1 More on Non-metals _______________________ are elements that are generally gases or brittle, dull-looking solids,

and poor conductors of heat and electricity. Group 17 is composed of highly reactive elements called _________________.

o Means “_____________-forming” Group 16 is called the oxygen group, but its formal name is the ___________________. Group 18 gases are extremely unreactive and commonly called _____________________.

o Previously called “__________ gases” because they rarely take part in a reaction; very ___________ = don’t react

____________________ have physical and chemical properties of both metals and non-metals, such as silicon and germanium.

In Summary Elements in the 1A-8A groups are called the representative elements The group B are called the transition elements Group 1A are the alkali metals (but NOT H) Group 2A are the alkaline earth metals Group 8A – Noble Gases Group 7A – Halogens Group 6A – Chalcogens Each Period is the _____________________ .

6.1 CheckWhat is a row of elements on the periodic table called?

A. octave B. period C. group D. transition

6.2 Classification of ElementsReview Vocabulary

valence electron: electron in an atom's outermost orbitals; determines the chemical properties of an atom

Main Idea - Elements are organized into different blocks in the periodic table according to their electron configurations.

Octet Rule Atoms gain, lose or share electrons to obtain a ______________________ ____________ (Noble

Gas electron configuration) Atoms want to be ____________ – lower energy state

Organizing Elements by Electron Configuration Recall electrons in the highest principal energy level are called valence electrons. All __________________ elements have _________ valence electron. The energy level of an element’s valence electrons indicates the period on the periodic table in

which it is found. The number of valence electrons for elements in groups 13-18 is ten less than their group

number.

What is silicon an example of? A. metal B. non-metal C. inner transition metal D. metalloid

The s-, p-, d-, and f- Block Elements The shape of the periodic table becomes clear if it is divided into blocks representing the atom’s

energy sublevel being filled with valence electrons. ______________ elements consist of group 1 and 2, and the element helium.

o Group 1 elements have a partially filled s orbital with one electron. o Group 2 elements have a completely filled s orbital with two electrons.

_______________ elements o After the s-orbital is filled, valence electrons occupy the p-orbital.o Groups 13-18 contain elements with completely or partially filled p orbitals.

The ________________ contains the transition metals and is the largest block.o There are exceptions, but d-block elements usually have filled outermost s orbital, and

filled or partially filled d orbital.o The five d orbitals can hold 10 electrons, so the d-block spans ten groups on the periodic

table. The ________________contains the inner transition metals.

o have filled or partially filled outermost s orbitals and filled or partially filled 4f and 5f orbitals.

o The 7 f orbitals hold 14 electrons, and the inner transition metals span 14 groups.

Diatomic Molecules Elements that come in __________ when pure – not in a compound. There are_____ of them:

o _______________________________________________ o Start at 7, make a ____, add Hydrogen

Oro Nof clbriha

______________ these!

6.2 CheckWhich of the following is NOT one of the elemental blocks of the periodic table? A. s-block B. d-block C. g-blockD. f-block

6.3 Periodic TrendsReview Vocabulary

principal energy level: the major energy level of an atomNew Vocabulary

ionionization energyoctet ruleelectronegativity

Which block spans 14 elemental groups?A. s-block B. p-block C. f-block D. g-block

Main Idea - Trends among elements in the periodic table include their size and their ability to lose or attract electrons

6.3 Atomic Radius Atomic size is a periodic trend influenced by _________________________________. For _____________, atomic radius is half the distance between adjacent nuclei in a crystal of the

element. For elements that occur as____________________, the atomic radius is half the distance

between nuclei of identical atoms. There is a general decrease in atomic radius from left to right, caused by increasing positive

charge in the nucleus.o Valence electrons are not shielded from the increasing nuclear charge because no

additional electrons come between the nucleus and the valence electrons. Atomic radius generally increases as you move down a group.

o The outermost orbital size increases down a group, making the atom larger.

6.3 Ionic Radius An ________ is an atom or bonded group of atoms with a positive or negative _____________. When atoms lose electrons and form positively charged ions, they always become smaller for

two reasons:1. The loss of a valence electron can leave an empty outer orbital resulting in a small radius.2. Electrostatic repulsion decreases allowing the electrons to be pulled closer to the radius.

When atoms gain electrons, they can become larger, because the addition of an electron increases electrostatic repulsion.

The ionic radii of positive ions generally decrease from left to right. The ionic radii of negative ions generally decrease from left to right, beginning with group 15 or

16. Both positive and negative ions increase in size moving down a group.

6.3 Ionization Energy _____________________________ is defined as the energy required to remove an electron

from a gaseous atom.o The energy required to remove the first electron is called the first ionization energy.o Removing the second electron requires more energy, and is called the second ionization

energy.o Each successive ionization requires more energy, but it is not a steady increase.

The ionization at which the large increase in energy occurs is related to the number of valence electrons.

First ionization energy increases from left to right across a period. First ionization energy decreases down a group because atomic size increases and less energy is

required to remove an electron farther from the nucleus. The _____________________ states that atoms tend to gain, lose or share electrons in order to

acquire a full set of eight valence electrons.o The octet rule is useful for predicting what types of ions an element is likely to form.

The ________________________ of an element indicates its relative ability to attract electrons in a chemical bond.

o Electronegativity decreases down a group and increases left to right across a period.

6.3 CheckThe lowest ionization energy is the ____. A. first B. second C. third D. fourth

The ionic radius of a negative ion becomes larger when:A. moving up a group B. moving right to left across period C. moving down a group D. the ion loses electrons

Ch 6 Key Concepts The elements were first organized by increasing atomic mass, which led to inconsistencies.

Later, they were organized by increasing atomic number. The periodic law states that when the elements are arranged by increasing atomic number,

there is a periodic repetition of their chemical and physical properties. The periodic table organizes the elements into periods (rows) and groups (columns); elements

with similar properties are in the same group. Elements are classified as either metals, nonmetals, or metalloids. The periodic table has four blocks (s, p, d, f). Elements within a group have similar chemical properties. The group number for elements in groups 1 and 2 equals the element’s number of valence

electrons. The energy level of an atom’s valence electrons equals its period number. Atomic and ionic radii decrease from left to right across a period, and increase as you move

down a group. Ionization energies generally increase from left to right across a period, and decrease as you

move down a group. The octet rule states that atoms gain, lose, or share electrons to acquire a full set of eight

valence electrons. Electronegativity generally increases from left to right across a period, and decreases as you

move down a group.