Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 2: Problem 9

Define these terms: (a) atomic number, (b) mass number. Why does a knowledge of atomic number enable us to deduce the number of electrons present in an atom?

Short Answer

Expert verified
Atomic number is the number of protons in an atom's nucleus which also equates to the number of electrons in a neutral atom. Mass number is the total number of protons and neutrons in an atom's nucleus. Knowing the atomic number lets us deduce the number of electrons an atom has because in a neutral atom, the number of protons (atomic number) and electrons are equal.

Step by step solution

01

Definition of Atomic Number

The atomic number of an atom is the number of protons in the nucleus of an atom. It uniquely identifies a chemical element. In an atom of neutral charge, atomic number is also equal to the number of electrons.
02

Definition of Mass Number

The mass number of an atom is the total number of protons and neutrons in the nucleus of an atom.
03

Relationship of Atomic Number to Electrons

As mentioned in Step 1, in a neutral atom, the atomic number is also equal to the number of electrons. This is due to the charge balance within the atom. The positively charged protons in the nucleus are balanced by the same number of negatively charged electrons orbiting it. Thus, knowing the atomic number of an atom allows us to deduce the number of electrons in it, given the atom is neutral.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Define these terms: (a) \(\alpha\) particle, (b) \(\beta\) particle, (c) \(\gamma\) ray, (d) X ray.

A sample of a radioactive element is found to be losing mass gradually. Explain what is happening to the sample.

Which of these are elements, which are molecules but not compounds, which are compounds but not molecules, and which are both compounds and molecules? (a) \(\mathrm{SO}_{2},\) (b) \(\mathrm{S}_{8},\) (c) \(\mathrm{Cs},\) (d) \(\mathrm{N}_{2} \mathrm{O}_{5},\) (e) O, (f) \(\mathrm{O}_{2},(\mathrm{~g}) \mathrm{O}_{3},(\mathrm{~h}) \mathrm{CH}_{4},\) (i) \(\mathrm{KBr},(\mathrm{j}) \mathrm{S},(\mathrm{k}) \mathrm{P}_{4},(\mathrm{l}) \mathrm{LiF}\)

Calculate the number of neutrons of \({ }^{239} \mathrm{Pu}\).

Name these compounds: (a) \(\mathrm{Na}_{2} \mathrm{CrO}_{4},\) (b) \(\mathrm{K}_{2} \mathrm{HPO}_{4}\) (c) HBr (gas), (d) HBr (in water), (e) \(\mathrm{Li}_{2} \mathrm{CO}_{3},\) (f) \(\mathrm{K}_{2} \mathrm{Cr}_{2} \mathrm{O}_{7},(\mathrm{~g}) \mathrm{NH}_{4} \mathrm{NO}_{2}\) (h) \(\mathrm{PF}_{3}\) (i) \(\mathrm{PF}_{5},\) (j) \(\mathrm{P}_{4} \mathrm{O}_{6}\) (k) \(\mathrm{CdI}_{2}\) - (I) \(\mathrm{SrSO}_{4},(\mathrm{~m}) \mathrm{Al}(\mathrm{OH})_{3},(\mathrm{n}) \mathrm{Na}_{2} \mathrm{CO}_{3} \cdot 10 \mathrm{H}_{2} \mathrm{O} .\)
See all solutions

Recommended explanations on Chemistry Textbooks

Ionic and Molecular Compounds

Read Explanation

Kinetics

Read Explanation

The Earths Atmosphere

Read Explanation

Physical Chemistry

Read Explanation

Chemistry Branches

Read Explanation

Making Measurements

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free