Question

Every chlorine atom has(1) 7 electrons (2) 17 neutrons
(3) a mass number of 35 (4) an atomic number of 17

Answer 1

The correct answer is (4). The atomic number of any element never changes. The atomic number is the number of protons an atom has and is the identifying characteristic of an atom. Hence, every chlorine atom has 17 protons, no more, no less, and consequently has an atomic number of 17. Different atoms of chlorine can have different numbers of electrons. This would give rise to ions. Different atoms of chlorine can have different number of neutrons, this results in isotopes. Because different atoms of chlorine can have different numbers of neutrons, they can have different mass numbers. The mass number is the sum of the number of protons (never changes for any given element) plus the number of neutrons (can change depending on the isotope of the element.)

Answer 2

Every chlorine atom has   $\boxed{\left( 4 \right){\text{ an atomic number of 17}}}$

Further explanation:

The smallest particle that is the building block of matter is known as an atom. Most of the space in an atom is empty and its mass is concentrated inside a small region called the nucleus.

Protons, electrons, and neutrons are the three subatomic particles that are present in the atom. Electrons revolve around the nucleus in definite orbits.

An atom is also written as $_{\text{Z}}^{\text{A}}{\text{X}}$ , where A is the atomic mass or mass number, Z is the atomic number and X is the letter symbol of the element.

Atomic number is equal to the number of protons present in the nucleus of the atom. Atomic mass is the total number of nucleons (protons and neutrons) within the atomic nucleus. It is also known as the mass number.

Isotopes:

Atoms of the same element with same atomic number but different mass numbers are called isotopes. These have the same number of protons but the number of neutrons is different. For example, $_{\text{6}}^{{\text{11}}}{\text{C}}$  and $_{\text{6}}^{{\text{12}}}{\text{C}}$  form isotopes of the same element carbon. These have the same atomic numbers (6) but different mass numbers (11 for $_{\text{6}}^{{\text{11}}}{\text{C}}$  and 12 for $_{\text{6}}^{{\text{12}}}{\text{C}}$ ).

Atomic number of any element is equal to the number of protons in it. But in case of neutral atom, it is also equal to the number of electrons. The atomic number of chlorine is 17 so the number of electrons in it is also 17 and therefore statement (1) is incorrect.

Chlorine exists in different isotopic forms that have different mass numbers so number of neutrons of every chlorine atom cannot always be the same. Therefore statements (2) and (3) are incorrect.

According to the position of chlorine in the periodic table, it is clear that its atomic number is 17. Every element has its own characteristic atomic number that is used to distinguish it from other elements. So every chlorine atom has an atomic number of 17. Therefore statement (4) is correct.

Learn more:

1. The major contribution of Antoine Lavoisier to chemistry: https://brainly.com/question/2500879

2. The number of significant figures: https://brainly.com/question/5222111.

Answer details:

Grade: High School

Subject: Chemistry

Chapter: Atomic Structure

Keywords: chlorine, atomic number, mass number, 17, periodic table, isotopes, same element, protons, electrons, neutrons, position, periodic table.