1. Complete the following: (a) Covalent bonds are one type of forces that are formed when two atoms electron(s) (b) Covalent compounds consists of two atoms (c) Single covalent bond: are formed when two atoms share pair of electrons. (d) Double covalent bond: are formed when two atoms share pairs of electrons. (e) Triple covalent bond: are formed when two atoms share pairs of electrons. (f) A molecule is a neutral groups of atoms that are held together by bonds (g) Diatomic molecule consists of atoms. (h) Molecular compound is made of bonded atoms

a) Van der Waals intermolecular forces

b) bonded

c) one pair

d) two pairs

e) three pairs

f) chemical bonds

g) two atoms

h) two or more covalently bonded atoms

Explanation:

(a) Covalent bonds are one type of Van der Waals intermolecular forces that are formed when two atoms share electron(s)

(b) Covalent compounds consists of two bonded atoms

(c) Single covalent bond: are formed when two atoms share one pair of electrons.

(d) Double covalent bond: are formed when two atoms share two pairs of electrons.

(e) Triple covalent bond: are formed when two atoms share three pairs of electrons.

(f) A molecule is a neutral groups of atoms that are held together by chemical bonds.

(g) Diatomic molecule consists of two atoms.

(h) Molecular compound is made of two or more covalently bonded atoms.

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e