Atoms

HideShow resource information

Atoms

All atoms are made up of subatomic particles

Proton               +1                 1

Neutron               0                 1

Electron             -1               >1

1 of 9

Inside an Atom

In an atom, in the nucleus, there are:

  • Protons and neutrons
  • Nucleus is overall positive as neutrons have no charge

In the energy levels called shells, there are:

  • Electrons
  • Atom overall has no charge as electrons are negative in the shells
2 of 9

Atomic and Mass Numbers

Atomic Number - Number of Protons in an element

- It is found at the bottom of an element

Mass Number - Number of Protons and Neutrons in an element

- It is found at the top of an element

3 of 9

The Periodic Table Basics

  • VERTICAL COLUMNS = GROUPS

  • ALL ELEMENTS IN A GROUP HAVE SAME NUMBER OF ELECTRONS IN THEIR OUTER SHELL
  • ELEMENTS IN GROUPS HAVE SIMILAR PROPERTIES
  • HORIZONTAL = PERIODS
4 of 9

Electron Arrangement

The pattern:

1st shell - can hold 2 electrons

2nd shell - can hold 2 electrons

3rd shell - when it holds 8 electrons

4th shell - A fourth can be made

5 of 9

Little facts on electron arrangement


Group 1 (The alkali metals) = 1 electron in outer shell

Group 2 (The alkaline earth metals) = 2 electrons in outer shell

Group 7 (The halogens) = 7 electrons in outer shell

Group 0 (The noble gases) = Full outer shell

6 of 9

Covalent Bonding

  • It is the process of sharing atoms
  • They only share electrons in their outer shells
  • Each covalent bond provides one extra shared electron for each atom
  • Each atom involved has to make enough covalent bonds to fill up its outer shell
  • They have no overall charge
7 of 9

In covalent bonds....

There are very WEAK INTERMOLECULAR FORCES (BETWEEN EACH MOLECULE)

Between each ATOM, there are verySTRONG INTRAMOLECULAR FORCES

8 of 9

Electronic Configuration of Ions

The Pattern: EXCEPT FOR B,C,Si,NE+AR

The elements Hydrogen, Lithium, Berillyum, Sodium, Magnesium, Aluminium, Potassium, Calcium LOOSE ELECTRONS TO HAVE A FULL OUTER SHELL

The elements Nitrogen, Oxygen, Fluorine, Phosphorus, Sulphur and Chlorine GAIN ELECTRONS TO HAVE A FULL OUTER SHELL  

9 of 9

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Atoms resources »