Periodic Table

of Elements

Cha

pter

6 N

otes

Modern Periodic Ta

ble

Designed by Demitri Mendeleev based on atomic mass (1869)

Modified by Henry Moseley based on atomic number (1926)

Classifying Elements

Properties of Metals & NonmetalsMetals

•Conduct heat & electricity•Malleable•Solid at room temp (except Hg)•High luster/sheen

Nonmetals•Poor conductors•Brittle•Most are gases at room temp•Solids (sulfur & phosphorus) are dull

Gold Bromine Gas

sToP & tHinK – metal or nonmetal

1. A gaseous substance that partially conducts electricity.

2. Solid that is malleable and shiny.3. Solid that is brittle and dull color.4. Solid that conducts electrical current and

has high luster.5. Has 7 valence electrons6. Found on the right of the ‘staircase’7. Has 1 valence electron8. d and f block elements

Elements in the same group have similar properties! (Periodic Law)

◦ Group 1 - Alkali Metals◦ Group 2 - Alkaline Earth Metals◦ d block - Transition Metals◦ f block - Inner Transition Metals◦ Group 7 - Halogens◦ Group 8 - Noble Gases

Reactivity increases from top to bottom for 1A, 2A Reactivity decreases from top to bottom for 7A

Classifying Elements – Let’s Look at the Periodic Chart

State the name of the group / family for each:◦ Magnesium◦ Bromine◦ Argon◦ Has 8 valence electrons◦ Group 1A◦ Copper◦ Tend to lose one electron to be more stable

(remember octet rule).

sToP & tHinK

A groups - representative elements (s and p blocks, except noble gases)◦ Display varied properties by column

B groups - transition elements & inner transition elements (d and f blocks)◦ Fairly similar properties

A Groups & B Groups

Atomic Radius

Decreases across the period (row/horizontal)

Increases down the group (column/vertical)

WHY?!? – 2 Reasons

1. Each added proton increases the positive

nuclear charge… as electrons are added to

principal energy levels the level gets smaller.

2. Electrons added to a new principal energy

level are ‘shielded’ from the positive nucleus

by the electrons in lower levels.

Let’s Look @ Atomic

Radius

1. Why does atomic radius decrease as you move from left to right on the PT?

2. Why does atomic radius increase as you move down each group on the PT?

SToP & THinK

Anions (- charged) larger than neutral atom of the same element

Anions Ionic Radius

Cation (+ charged) smaller than neutral atom of the same element

Cations Ionic Radius

1. Which has a larger radius for each: ◦ K or K+? ◦ S or S2-?

2. Explain why.

SToP & THiNk

The amount of energy required to remove an electron from an atom.

Increases up the periodic chart and from left to right.

Ionization

Energy(IE)

Trends

Ionization Energy

(IE)Trends

(IE)

Incre

ases U

p t

he P

eri

od

ic

Ch

art

.

(IE) Increases from Left to Right

The ability of an atom to pull electrons in a chemical bond.

Due to pull from protons and how close electrons are to nucleus.

More electronegative = stronger pull on electrons

Same pattern as ionization energy (IE)

ElectronegativityTrends

Which is more electronegative?◦ Ca or Cl◦ P or O

In your own words, explain why ionization energy and electronegativity follow the same trend pattern on the periodic table.

SToP & THiNk