Electrons and Ions

Question 1

Electron Shells

Answer 1

• Electrons spin around the nucleus in electron shells.
• The attraction between the nucleus and first-shell electrons is the strongest.
• The further out electron shells are, the larger they are and the more electrons can fit in them.
• The maximum number of electrons a shell can hold is calculated by the formula 2 x n (squared), n is the number of the shell.

Question 2

Electron Configuration

Answer 2

• Electrons fill shells from the lowest level outwards.
• We can represent electron configuration using Bohr diagrams.
• Shell 1 (2) 2(8) 3(8).
• Electrons are equal to the number of protons.

Question 3

Ions

Answer 3

• An Ion is any atom or group of atoms that has one or more positive or negative electrical charges.
• An Ion is formed when an atom gains or loses electrons.
• Cations are positive.
• Anions are negative.

Question 4

Ionic Bonding

Answer 4

• When the outermost electrons of atoms interact and cause atoms to join together, a new chemical bond is formed.
• Electrons can be transferred between atoms (Ionic bonding).
• Electrons can be shared between atoms (Covalent Bonding )
• Electrons can move freely between atoms (Metallic Bonding).

Question 5

Ionic Compound Formula

Answer 5

• The positive ion (usually a metal ion) is written first.
• The negative ion (non-metal ion) is written second.
• The number of each ion is adjusted so that the total positive charge equals the total negative charge.
• Subscripts are used to indicate the number of each ion present.