Answers:
(1) Covalent
(2) Covalent
(3) None
(4) Covalent
Step-by-step explanation:
Element x is in Group 14 (carbon family); Element y is in group 17 (halogens); Element z is in Group 18 (noble gases).
Bonds between nonmetals are covalent bonds formed by sharing electrons.
(1) The x-x bonds are probably covalent bonds in a network solid, because it is difficult to form four covalent bonds between two atoms.
(2) Each y atom needs one electron to complete its octet. If they each share one electron, they will both have a octet. The y-y bond will be a single covalent bond.
(3) Each z atom is a noble gas. Noble gases do not form z-z bonds, because they already have an octet.
(4) Each xy₄ molecule will have four polar covalent x-y bonds pointing toward the corners of a regular tetrahedron.
