minimum of three as in NH3, PCl3
maximum of five as in PCl5
Why does group 4A elements tend to form covalent bonds rather than ionic bonds? 
Group-14 elements share electrons. they form covalent bonds.
All non-metals in group IV will be able to form 4 covalent bonds with other elements. They need 4 more electrons to form the octet structure in their valence shell. Hence, they can form 4 single covalent bonds to constitute the covalent structure. On the other hand, elements in group III, such as boron, can also make 1 double bond and 3 single bonds to share 5 electrons to achieve octet structure.
generally group 1
Only halogens and members of the oxygen group can form diatomic molecules joined by a single covalent bond.
Why does group 4A elements tend to form covalent bonds rather than ionic bonds? 
Group-14 elements share electrons. they form covalent bonds.
All non-metals in group IV will be able to form 4 covalent bonds with other elements. They need 4 more electrons to form the octet structure in their valence shell. Hence, they can form 4 single covalent bonds to constitute the covalent structure. On the other hand, elements in group III, such as boron, can also make 1 double bond and 3 single bonds to share 5 electrons to achieve octet structure.
generally group 1
Only halogens and members of the oxygen group can form diatomic molecules joined by a single covalent bond.
yes.
The only group of neutral elements is the noble gases. They are in group 0. They are electronically stable elements that do not tend to react. They exist as single molecules.
4
Elements in group 17 need one electron to gain a stable electron configuration. Two atoms of the same element or two elements in this family forms compounds with a single covalent bond. Examples are chlorine, bromine or iodine chloride.
Two oxygen atoms, you sneaky person, you.
The elements of V- A group of periodic table form three covalent bonds as Nitrogen forms NH3 and phosphorus forms PH3.
So basically covalent starts with a c just like the group carbon does on the periodic table, thus, group 14 form covalent bonds. That's how I always remember it. While on the other hand group 1 and 17 form ionic bonds.