Download - Ions2
The importance of a full outer shellPart 11
When an atom gains or loses an electron it becomes an ION.
It now has either a positive or negative chargeNegative if it gains an electron -
AnionPositive if it loses an electron -
CationNon-metals gain electronsMetals lose electrons
Working out the charge:
16p-18e = -2
Oxygen has 8 protons
8 electrons + 2 = 10
8p – 10e = -2 4p-2e = +2
Ion Notation
Na1+Chemical symbol
Charge(1 electron lost)
How many electrons? Mg2+
p – e = charge12 – e = +212 = 2 + e12 – 2 = e e = 10
electrons
Mg2+Mg has 12
electrons if neutral
A charge of 2+ means it has lost 2 electrons
12 – 2 = 10
OR
Let’s practice
Cl has 17 protons- Charge = gain electron
17 + 1 = 18
7+3 = 10 13 – 3 = 10
Ca2+P3-
Give the ion notation for an atom with 11 protons and 10 electrons
Na1+