Remember, covalent compounds are compounds with bonds between two non-metals. Ionic bonds are those between a metal and a non-metal.
To determine if an element is a metal or non-metal, simply look at the periodic table! So...
a. Li is found on the left side while F is found on the right. A bond between a metal and a non-metal. This is an ionic bond.
b. Mg is found on the left side while S is found on the right. A bond between a metal and a non-metal. This is an ionic bond.
c. This is a tricky one. ammonia, or NH3, is covalent. You just have to remember this one. It has no net charge, unlike its brother NH4 (which has a 1+ charge put is still covalently bonded). Hydrogen has weird properties!
d. Ca is found of the left side while Cl is found on the right. A bond between a metal and a non-metal. This is an ionic bond. Also consider the charges! Ca has a charge of 2+ but Cl only has a charge of 1-. This is why there are 2 Cloride atoms.
The answer should be 1 because they need senators to be away from the political pressure from the general public but it makes more sense than the rest
Combination reaction also called synthesis reaction, the product will always be a compound.
For example:
A + B -> AB
C2 + O2 -> CO2
H2+Cl2 -> HCl
No, because HPO₄ is a multi-atom ion and has its own name which is Hydrogen phosphate.