1. State the composition of the nucleus.
2. Describe the arrangement of the electrons
3. Name the element for which the atom is an isotope and
4. State its valency.
SOLUTION
1. Nucleus = 13 protons + 14 Neutrons, Atomic mass = 27
2. Electronic configuration = 1s² 2s² 2P6 3s² 3P¹
OR K Shell = 2 electrons; L Shell = 8 Electrons; M Shell = 3 Electrons
3. Aluminium (Al).
4. Valency = 3