1.6 Periodic table

IE across a period

first ionisation energy increases across a period.

IE down a group

First ionisation energy decreases down a group

There is a decrease between Group 2 and 3 IE

Group 3’s outer electron is partly shielded by the s electrons/ at higher energy level

There is a decrease between Group 5 and 6

because of electron-electron repulsion between the electron pair in one p orbital.

Electronegativity

increases across a period because there is an increase in nuclear charge, but the bonding electrons are always shielded by the same inner electrons.

Oxidation

• lost of electrons

• Gain of oxygen

• Loss of hydrogen

• Oxidation number increases

Reduction

• gain of electrons

• loss of oxygen

• gain of hydrogen

• oxidation number decreases

reducing agent

a species that donates electrons; it becomes oxidised itself in the process.

oxidising agent

is a species that accepts electrons; it becomes reduced itself in the process.

Metal oxides

• are basic

• dissolve in aqueous solution to form an alkaline solution.

Non metal oxides

they are acidic they dissolve in aqueous solution to give an acidic solution.

Melting point down group 2

the melting points generally get lower as you go down the group because the metallic bonds get weaker.

Group 1 solubility

carbonates, sulfates, nitrates and hydroxides are all soluble. (aq)

Group 2 solubility

all carbonates are insoluble (s)

Hydroxides solubility

increases down the group

Sulfates solubility

decreases down the group

Test for a sulfate ion

• add hcl then a barium chloride solution.

• if sulfate is present a white precipitate will form.

Thermal stability

increases in both (group 1/2) as you go down the group