Chemistry of life help !

1. The three particles that make up atoms are
a. protons, neutrons, and isotopes.
b. neutrons, isotopes, and electrons.
c. positives, negatives, and neutrals.
d. protons, neutrons, and electrons.


2. If an atom contains 3 protons, 4 neutrons, and 3
electrons, its mass number is
a. 3.
b. 4.
c. 7.
d. 11.


3. Isotopes are atoms of the same element with the
same number of protons and a different number of
a. electrons.
b. molecules.
c. neutrons.
d. ions.


4. Which of the following is a substance formed by
the chemical joining of two or more elements in
definite amounts?
a. compound
b. isotope
c. nucleus
d. enzyme


5. Which of the following makes up a molecule of
water?
a. one atom of hydrogen and one atom of oxygen
b. one atom of sodium and one atom of chlorine
c. one atom of hydrogen and two atoms of oxygen
d. two atoms of hydrogen and one atom of oxygen


6. In a water molecule, shared electrons spend more
time around the oxygen atom than the hydrogen
atoms. As a result, the oxygen atom is
a. slightly negative.
b. very negative.
c. slightly positive.
d. very positive.


7. Which of the following statements about a
compound is true?
a. The physical and chemical properties of a
compound are usually very different from those
of the elements from which it is formed.
b. Only the physical properties of a compound are
usually the same as those of the elements from
which it is formed.
c. Only the chemical properties of a compound
are usually the same as those of the elements
from which it is formed.
d. The physical and chemical properties of a
compound are usually the same as those of the
elements from which it is formed.

8. A covalent bond is formed as the result of
a. transferring electrons.