Chapter 2, Problem 1TYK

Summary Introduction

a.

To determine:

The element that has atomic number 24.

Introduction:

The basic and smallest unit that forms all substances is an atom. The interaction of atoms results in the formation of molecules. The atoms have three important components. These are electrons, protons, and neutrons. The neutrons and protons are present inside the nucleus of the atom while the electrons revolve around the nucleus of the atom.

Explanation of Solution

The total number of protons present inside the nucleus of an atom is called the atomic number. Different atoms have different atomic numbers. The atoms join together to form a larger molecule called element. The scientists have developed a table that represents all the elements according to their atomic number.

According to the periodic table, the element that has atomic number 24 is chromium.

Summary Introduction

b.

To determine:

The number of neutrons that are present in the element whose atomic number is 24.

Introduction:

The atoms contain positively charged particles, negatively charged particles, and the neutral particles. The particles with a positive charge are called protons. However, the particles with a negative charge are known as electrons. However, the neutrally charged particles are called neutrons.

Explanation of Solution

The number of neutrons present in the nucleus of an atom depends upon the atomic number of element and its atomic mass.

$\begin{array}{rll}\text{Atomic number of chromium}& =& \text{24}\\ \text{Atomic mass of chromium}& =& \text{52}\end{array}$

The formula to be used is as follows:

$\text{Number of neutrons}=\text{Atomic mass}-\text{Atomic number}$

Substituting the information in the given formula:

$\begin{array}{rll}\text{Number of neutrons in chromium}& =& 52-24\\ \text{Number of neutrons in chromium}& =& 28\end{array}$

Thus, 28 neutrons are present in the element whose atomic number is 24.

Summary Introduction

c.

To determine:

The number of electrons present in the neutral atom of an element whose atomic number is 24.

Introduction:

The element that has atomic number 24 is chromium. The atoms that have no overall charge present on them are known as the neutral atom. The neutral atoms have no force of attraction or force of repulsion.

Explanation of Solution

The neutral atoms have no charge. This is because the negative charge cancels the positive charge. A neutral atom has number of protons equal to the number of electrons.

The neutral chromium element has 24 protons. This indicates that a neutral chromium ion has 24 electrons as number of protons is equal to the number of electrons in a neutral element.