Atomic Structure Quiz

Questions and Answers

What is the fundamental building block of matter?

Proton

Molecule

Electron

Atom (correct)

Why do objects become electrically charged when rubbed together?

Because of the presence of molecules

Because they lose electrons

Because of the presence of charged particles in an atom (correct)

Because they gain protons

Who identified the electron?

E. Goldstein

Galileo

J.J. Thomson (correct)

Dalton

What was the term given by E. Goldstein to the new radiations in a gas discharge?

Canal rays Signup and view all the answers

What was the major challenge before scientists at the end of the 19th century?

To reveal the structure of the atom Signup and view all the answers

What is the reason for the existence of different kinds of matter?

Because of different atoms Signup and view all the answers

What was Dalton's proposal about atoms?

Atoms are indivisible Signup and view all the answers

What is the name of the chapter that deals with the structure of the atom?

Chapter 4 Signup and view all the answers

What is the significance of the discovery of canal rays?

It led to the discovery of another sub-atomic particle Signup and view all the answers

What is the symbol used to denote the mass number of an atom?

A Signup and view all the answers

What is the valency of fluorine according to the content?

One Signup and view all the answers

What is the valency of oxygen calculated from the content?

Two Signup and view all the answers

What is the combining capacity of an atom known as?

Valency Signup and view all the answers

What is the number of protons present in the nucleus of an atom known as?

Atomic Number Signup and view all the answers

What is the notation for an atom that includes the atomic number, mass number, and symbol of the element?

$$Z\ X_A$$ Signup and view all the answers

What is the atomic number of an atom with 8 electrons and 8 protons?

8 Signup and view all the answers

What is the purpose of knowing the valency of an element?

To know the combining capacity of an atom Signup and view all the answers

What is the term used to describe the different atoms of the same element with different mass numbers?

Isotopes Signup and view all the answers

What is the reason for calculating the average mass of an element?

Because the element exists in isotopic forms Signup and view all the answers

Who is credited with the discovery of electrons?

J.J.Thomson Signup and view all the answers

What was the major limitation of Rutherford's model of the atom?

It could not explain the stability of the atom Signup and view all the answers

What is the significance of the atomic shells being complete in Bohr's model?

The atom becomes less reactive Signup and view all the answers

What is the term used to describe atoms that have the same atomic number but different mass numbers?

Isotopes Signup and view all the answers

Who discovered the presence of neutrons in the nucleus of an atom?

J.Chadwick Signup and view all the answers

What was the significance of Rutherford's alpha-particle scattering experiment?

It led to the discovery of the atomic nucleus Signup and view all the answers

What is the term used to describe atoms that have the same mass number but different atomic numbers?

Isobars Signup and view all the answers

What is the distribution of electrons in Neils Bohr's model of the atom?

Electrons are distributed in different shells with discrete energy around the nucleus Signup and view all the answers

What is the charge of neutrons?

No charge Signup and view all the answers

What determines the valency of an atom?

The number of electrons in the outermost shell Signup and view all the answers

What is the atomic number of an element?

The number of protons in the nucleus Signup and view all the answers

What is the difference between isotopes and isobars?

Isotopes have different mass numbers, while isobars have the same mass number Signup and view all the answers

What is the mass of an electron compared to the mass of a hydrogen atom?

About 1/2000 the mass of a hydrogen atom Signup and view all the answers

What are the shells of an atom designated as?

K, L, M, N... Signup and view all the answers

What determines the element of an atom?

The number of protons in the nucleus Signup and view all the answers

What is the mass number of an atom?

The sum of protons and neutrons in the nucleus Signup and view all the answers

What is the term for the combining capacity of an atom?

Valency Signup and view all the answers

What was discovered through Rutherford's alpha-particle scattering experiment?

Atomic Nucleus Signup and view all the answers

What is the characteristic that defines isotopes of an element?

Different number of neutrons Signup and view all the answers

How many valence electrons are present in a Cl– ion?

8 Signup and view all the answers

What is the correct electronic configuration of sodium?

2,8,1 Signup and view all the answers

What can be inferred about the atomic species with 10 neutrons and 9 protons?

It is an isotope of fluorine Signup and view all the answers

What is the number of protons in the atomic species with 16 neutrons and named sulphur?

12 Signup and view all the answers

What can be inferred about the atomic species with 24 protons and 12 electrons?

It is a metal Signup and view all the answers

What is the number of neutrons in the atomic species with 2 protons and 1 electron?

0 Signup and view all the answers

What can be inferred about the atomic species with 1 proton and no neutrons?

It is a hydrogen atom Signup and view all the answers

Study Notes

Structure of the Atom

Atoms are the fundamental building blocks of matter, and their existence is due to different atoms constituting them.

Atomic Number and Mass Number

Atomic number is the number of protons present in the nucleus of an atom.
Mass number is the sum of the total number of protons and neutrons present in the nucleus of an atom, denoted by 'A'.
Atomic number, mass number, and symbol of the element are to be written as: ZXA.

Valency

Valency is the combining capacity of an atom, which can be calculated by identifying the number of electrons in the outermost shell.
Elements have a definite combining capacity, and valency can be calculated for different elements.

Sub-atomic Particles

Electrons are negatively charged, protons are positively charged, and neutrons have no charge.
Electrons are embedded in a positive sphere (proposed by J.J. Thomson).
Protons and neutrons are present in the nucleus of an atom.
Neils Bohr proposed that electrons are distributed in different shells with discrete energy around the nucleus.

Rutherford's Model

Rutherford's alpha-particle scattering experiment led to the discovery of the atomic nucleus.
Rutherford proposed that a very tiny nucleus is present inside the atom, and electrons revolve around this nucleus.

Limitations of Models

Limitations of J.J. Thomson's model: did not explain the stability of the atom.
Limitations of Rutherford's model: did not explain the stability of the atom.
Neils Bohr's model was more successful in explaining the stability of the atom.

Isotopes and Isobars

Isotopes are atoms of the same element, which have different mass numbers.
Isobars are atoms having the same mass number but different atomic numbers.
Elements are defined by the number of protons they possess.

Electronic Configuration

Shells of an atom are designated as K, L, M, N, etc.
Valency is related to the electronic configuration of an atom.
The electronic configuration of an atom can be written by identifying the number of electrons in different shells.

Exercises and Questions

Compare the properties of electrons, protons, and neutrons.
Describe Bohr's model of the atom.
Explain the rules for writing the distribution of electrons in various shells for the first eighteen elements.
Define valency by taking examples of silicon and oxygen.
Explain isotopes, mass number, atomic number, and isobars with examples.

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Description

Test your knowledge of atomic structure, including atomic number, mass number, and valency. Learn about the building blocks of matter and how atoms are constituted.