Question

2.18 Determine whether each of the following statements is

true or false; if false, correct the statement to make it
true: (a) The nucleus has most of the mass and compris-
es most of the volume of an atom; (b) every atom of a
given element has the same number of protons; (c) the
number of electrons in an atom equals the number of
neutrons in the atom; (d) the protons in the nucleus of
the helium atom are held together by a force called the
strong nuclear force.

Answer 1

(a) False

(b) True

(c) False

(d) True

Step-by-step explanation:

Option A is false. The nucleus has most of the mass in a small volume thus making it very dense. But the volume is given by the atomic radius that is the distance between the center of the nucleus and the electrons in different atomic orbitals.

Option B is true. Every atom of an element has the same atomic number. Atomic number is the total number of protons in an atom.

Option C is false. In a neutral atom the number of electrons is equal to the number of protons. Neutrons are neutral in charge.

Option D is true. All protons are positively charged and similar charges repel each other with electrostatic forces of repulsion but the nuclear forces overcome the repulsive forces and stabilize the protons in the nucleus of the atom.

Answer 2

(a) The nucleus has most of the mass and comprises most of the volume of an atom; false

The nucleus has most of the mass but the volume of an atom is depends on the distance between the nucleus and the position of the electrons.

(b) Every atom of a given element has the same number of protons; true

They may have different number of neutrons and so you have isotopes but the number of protons remain the same for a given element.

(c) The number of electrons in an atom equals the number of neutrons in the atom; false

The number of electrons in an atom equals the number of protons in the atom.

The electrons are negatively charged which compensate the positively charged protons not the neutrons which do not have a charge (they are neutral).

(d) The protons in the nucleus of the helium atom are held together by a force called the strong nuclear force. true