Solution:
i. Formula mass is the mass of all atoms/ ions and in formula (of a compound or an ion) formula mass of NaCl = 23+35.5g = 58.5g
ii. Ionic equation is the chemical equation of reaction using the ions that are involved in the reaction as reactants and products.
e.g. NaOH+Hcl → NaCl + H2O
Na+ OH¯ + H+ Cl¯ → NaCl + H2O
iii. Allotropes are the different forms of an element in the same physical state. E.g. Allotropes of carbon are coal, diamond, graphite e.t.c.
iv. Covalent bonding occurs when pairs of electrons are shared between two atoms to form bonds. e.g. bonds between carbon and hydrogen in hydrocarbon molecules.
