Question

Which of the following statements are true? (a) Neutrons have neither mass nor charge. (b) Isotopes of an element have an identical number of protons. (c) C-14 and N-14 have identical neutron/proton \(\left(n / p^{+}\right)\) ratios. (d) The vertical columns in a periodic table are referred to as "groups." (e) When an atom loses an electron, it becomes positively charged.

Short answer

Question: Determine the truth of each statement about atomic structure and periodic table organization. Provide a short explanation for each. a) Neutrons have neither mass nor charge. b) Isotopes of an element have an identical number of protons. c) C-14 and N-14 have identical neutron/proton ratios. d) The vertical columns in a periodic table are referred to as "groups." e) When an atom loses an electron, it becomes positively charged. Answer: a) False. Neutrons do have mass, but they do not have any charge. b) True. Isotopes have the same number of protons but different numbers of neutrons. c) False. C-14 and N-14 have different neutron/proton ratios. d) True. The vertical columns in the periodic table are called groups. e) True. When an atom loses an electron, it becomes positively charged.

Step-by-step solution

(a) Neutrons have neither mass nor charge.

This statement is false. Neutrons are particles found in the nucleus of an atom. While they do not have any charge, they do have mass. Their mass is approximately equal to that of a proton.

(b) Isotopes of an element have an identical number of protons.

This statement is true. Isotopes of an element are characterized by having the same number of protons (which defines the element) but a different number of neutrons.

(c) C-14 and N-14 have identical neutron/proton \(\left(n / p^{+}\right)\) ratios.

This statement is false. C-14 (Carbon-14) has 6 protons and 8 neutrons, while N-14 (Nitrogen-14) has 7 protons and 7 neutrons. Thus, the neutron/proton ratios are different: C-14 has a ratio of \(\frac{8}{6}=\frac{4}{3}\), while N-14 has a ratio of \(\frac{7}{7}=1\).

(d) The vertical columns in a periodic table are referred to as "groups."

This statement is true. The vertical columns in the periodic table are called groups, and elements within the same group have similar chemical properties because they have the same number of valence electrons.

(e) When an atom loses an electron, it becomes positively charged.

This statement is true. When an atom loses an electron, it is left with more protons than electrons, resulting in a net positive charge. Such an atom is called a cation.

Key concepts

Neutron/Proton Ratio

Understanding the neutron/proton ratio is essential in the study of isotopes and nuclear chemistry. Isotopes are variants of a particular chemical element that have the same number of protons but different numbers of neutrons within their atomic nuclei.

For example, Carbon-12 and Carbon-14 are isotopes of carbon. Carbon-12 has 6 protons and 6 neutrons, while Carbon-14 has 6 protons and 8 neutrons. It's this difference in the number of neutrons that influences the neutron/proton ratio. This ratio is critical in determining the stability of an isotope; isotopes with a ratio that is too high or too low can be radioactive.

In the exercise, the neutron/proton ratio was compared between C-14 and N-14, which demonstrated that even if two isotopes have the same atomic mass number (total number of protons and neutrons), they can have a different neutron/proton ratio, affecting their chemical and physical properties significantly.

Periodic Table Groups

The periodic table is an organized chart of the chemical elements, arranged by their atomic number, electron configuration, and recurring chemical properties. The vertical columns of the table are known as 'groups' and are very important in classifying elements.

Elements in the same group typically have similar properties and the same number of electrons in their outermost shell, known as valence electrons. These shared characteristics make elements within a group behave similarly chemically. For instance, group 1 contains the alkali metals, which are highly reactive and have one valence electron, whereas group 17 contains the halogens, which are reactive non-metals with seven valence electrons.

Understanding the layout and the grouping of elements in the periodic table allows scientists and students to predict and explain how different elements will react and bond with each other.

Cation

An ion is an atom or molecule with a net electric charge due to the loss or gain of one or more electrons. When an atom loses an electron, it becomes a cation, which is a positively charged ion. The cation takes its name from the Greek word 'kation,' meaning 'going down,' which refers to the descending movement of cations in an electric field in electrolysis.

The concept of cations is essential in understanding chemical reactions, especially those in ionic compounds. For example, in a sodium chloride (table salt) crystal, sodium (Na) loses an electron to become Na+, a cation, while chlorine (Cl) gains an electron to become Cl−, an anion. Here, the cation is responsible for the positive charge balance within the crystal lattice.

In the biological context, cations like potassium (K+) and calcium (Ca2+) are vital for cell function, mediating vital processes such as muscle contraction and nerve impulse transmission.