Periodic Table

Group 2

Alkaline earth metal

Have 2 valence electron

Electropositivity increases down the group

Reactivity increases down the group

Have 2 valence electron therefore, release 1 electron during a chemical reaction to attain a stable octet arrangement.

Transition Element

Transition elements:
- Can have more than 1 oxidation number

- Example: Fe2+, Fe3+

Can form ion with different changes

Form compund of different colour

Solubility of each product of a transmittion element varies

Group 17

Halogen (F, Cl, Br, I, Al)

Have 7 valence electron (exist as diatomic)

Electronegativity decreases down the group

Reactivity decreses when down the group

Have 7 valence electron therefore release 7 electron

F (colourless), Cl (greenish yellow), Br (dark brown), I (black)

Example:

-2Cl2+2H2O→4HCl+O2
Forms O2 and acid (HCl) when react with water

2Na+Cl2→2NaCl
Form metal halide

NaOH+HCl→NaCl+H2O
Form salt and water

Group 18

Noble gas or inert gas (He, Ne, Ar, Kr, Xe, Rn)

Outermost shell is completely filled with electron

Very stable and unreactivity

Exist as monoatom (single atom)

Has an octet electron arrangement therefore no sharing or accepting electronis needed

History

Dimtri Mendelev arranged the elements in the order of incresing atomic mass.

The current periodic table is arranged in order of incresing proton number in relation to the electron arrangement.

(Across the periodic table)

High valence electron number:
- Stronger force of attraction between nucleus and valence

- More likely to accept electron

Low valence electron number:
- Weaker force of attraction between nucleus and valence

- More likely to donate

(Down the periodic table)

Contary with the number of valence electron at the outermost shell:

- Group 1 more unstable moving down the periodic table. Weak Van der Waals forces

- Group 17 most stable moving down the periodic table. Strong Van der Waals forces

Characteristic
(Groups)

Vertical columns are called groups and there are 18 groups in total.

Member of a group share similar chemical properties but different physical properties going down the group.

Groups are divided base on the valence electron starting from 1 (Periods).

Horizontal rows are called periods and there are in total.

Periods also indicates the amount of shells filled by the electrons of the element.

Consist of metals and non-metal elements:

- Metals react with non-metal element to form ionic compound.

- Non-metal and non-metal element from covalent compund.

Group 1

Alkali metal (Li, Na, K, Rb, Cs, F) except H

Have 1 valence electron