Which of the following statements is true?
(a) Atoms of the same element may have different masses.
(b) Atoms may be divided in ordinary chemical reactions.
(c) Atoms can never combine with any other atoms.
(d) Matter is composed of large particles called atoms.
Answer: (a)
The mass of a neutron is
(a) about the same as that of a proton.
(b) about the same as that of an electron.
(c) double that of a proton.
(d) double that of an electron.
Answer: (a)
The nucleus of most atoms is composed of
(a) tightly packed protons.
(b) tightly packed neutrons.
(c) tightly packed protons and neutrons.
(d) loosely connected protons and electrons.
Answer: (c)
