Free NEX Basic Chemistry: Atomic Structure and Chemical Reactions Questions and Answers

Question 1

Which subatomic particle has a negative charge and orbits the nucleus of an atom?

Accepted Answer

Electron

Answer

Electrons are negatively charged particles that exist in shells or orbitals around the central nucleus. Protons are positive and neutrons are neutral, both located within the nucleus.

Question 2

The atomic number of an element is determined by the number of ___ in one atom of that element.

Accepted Answer

protons

Answer

The atomic number is the defining characteristic of an element. It is equal to the number of protons found in the nucleus of every atom of that element.

Question 3

In the chemical reaction Zn + 2HCl → ZnCl₂ + H₂, the products are:

Accepted Answer

ZnCl₂ and H₂

Answer

In a chemical equation, the substances on the left side of the arrow are the reactants (what you start with). The substances on the right side of the arrow are the products (what is formed).

Question 4

Isotopes of an element are atoms that have the same number of protons but a different number of ___.

Accepted Answer

neutrons

Answer

Isotopes are variants of a particular chemical element. While all isotopes of a given element have the same number of protons, they differ in the number of neutrons in their nuclei.

Question 5

The reaction 2H₂O → 2H₂ + O₂ is an example of which type of reaction?

Accepted Answer

Decomposition

Answer

A decomposition reaction is one in which a single compound breaks down into two or more simpler substances. Here, water (H₂O) is breaking down into hydrogen (H₂) and oxygen (O₂).

(NEX) Nursing Entrance Exam Practice Test

(NEX) Nursing Entrance Exam Practice Test

Free NEX Basic Chemistry: Atomic Structure and Chemical Reactions Questions and Answers