An Introduction to Atomic Number, Isotopes and Isobars

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Atomic Number and Mass Number

The revelation of subatomic particles gave a ton of information about the properties of the chemical elements and their isotopes. Moseley gave the hypothesis that the modern periodic table proposed by Mendeleev depended on the number of protons in the nucleus of a particle. Moseley's hypothesis depended on the study of wavelengths of X-rays that were discharged by chemical elements. It was this hypothesis that established the framework for the atomic number. This article would give you an introduction to atomic number, isotopes, and isobars.

We will learn about the atomic number and mass number, the atomic mass definition, atomic mass formula, atomic weight, and take a look at the atomic mass of all elements.


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Atomic Number

Let us now define the atomic numbers.

The number of protons presents in the nucleus of an atom is known as the atomic number. It is commonly spoken to by Z. It has been set up that the charge of a proton is equal yet opposite to that of an electron. Since a molecule is electrically impartial and neutrons convey no electrical charge, the number of electrons and protons in an unbiased particle is the equivalent. This infers that the atomic number equals the number of electrons or the number of protons in a given molecule. As we realize that elements will in general lose or pick up electrons during numerous chemical reactions, the number of protons is conventionally used to speak to the atomic number of an element. Hydrogen atomic mass number of one as it has just a single proton in its molecule.


Atomic Mass Number

It is the absolute number of protons and neutrons present in the nucleus of an atom. Protons and neutrons present in the nucleus of an atom are together called as nucleons and henceforth the mass number is the number of nucleons present in a molecule. The mass number is spoken to by A. Example: Nitrogen has a mass number of 14 as it has 7 protons and 7 neutrons in its molecule.


Isotopes and Isobars

Those elements that have a similar atomic number yet an alternate mass number are alluded to as isotopes. Isotopes happen because of the presence of an alternate number of neutrons in elements having a similar atomic number as mass number is the aggregate of the number of neutrons and protons. Numerous yet not all elements have isotopes. The isotopes of hydrogen are protium (has one proton and no neutrons), deuterium (has one proton and one neutron) and tritium (has one proton and two neutrons). The chemical properties of isotopes are similarly inferable from the way that they have a similar number of protons and subsequently the similar number of electrons which decides the chemical properties of an element.


Isobars, then again, are the atoms having a similar mass number however an alternate atomic number. For example, the atomic mass of carbon and nitrogen is 6 and 7 individually. Carbon-14, which is an isotope of carbon, has an atomic mass number 14, the same as nitrogen and henceforth both carbon-14 and nitrogen are isobars.

FAQ (Frequently Asked Questions)

1. Define Mass Number.

Ans: The mass number refers to the complete number of protons and neutrons (together known as nucleons) in an atomic nucleus. It is approximately equal to the atomic (otherwise called isotopic) mass of the molecule expressed in atomic mass units. Since protons and neutrons are the two baryons, the mass number An is indistinguishable with the baryon number B as of the nucleus as of the entire molecule or ion. The mass number is distinctive for each unique isotope of a chemical element. Henceforth, the contrast between the mass number and the atomic number Z gives the number of neutrons (N) in a given nucleus: N = A − Z.

2. What is the Atomic Mass of Oxygen?

Ans: For some random isotope, the aggregate of the numbers of protons and neutrons in the nucleus is known as the mass number. This is because of every proton and every neutron gauge one atomic mass unit (amu). By including the number of protons and neutrons and increasing by 1 amu, you can figure the mass of the atom. Oxygen, having the symbol O, has 8 as its atomic number.

3. What is the Atomic Mass of the First 50 Elements?

Ans:


Atomic Number

Atomic Mass

Chemical Element Name

Symbol

1

1.0079

Hydrogen

H

2

4.0026

Helium

He

3

6.941

Lithium

Li

4

9.0122

Beryllium

Be

5

10.811

Boron

B

6

12.0107

Carbon

C

7

14.0067

Nitrogen

N

8

15.9994

Oxygen

O

9

18.9984

Fluorine

F

10

20.1797

Neon

Ne

11

22.9897

Sodium

Na

12

24.305

Magnesium

Mg

13

26.9815

Aluminum

Al

14

28.0855

Silicon

Si

15

30.9738

Phosphorus

P

16

32.065

Sulfur

S

17

35.453

Chlorine

Cl

18

39.948

Argon

Ar

19

39.0983

Potassium

K

20

40.078

Calcium

Ca

21

44.9559

Scandium

Sc

22

47.867

Titanium

Ti

23

50.9415

Vanadium

V

24

51.9961

Chromium

Cr

25

54.938

Manganese

Mn

26

55.845

Iron

Fe

27

58.9332

Cobalt

Co

28

58.6934

Nickel

Ni

29

63.546

Copper

Cu

30

65.39

Zinc

Zn

31

69.723

Gallium

Ga

32

72.64

Germanium

Ge

33

74.9216

Arsenic

As

34

78.96

Selenium

Se

35

79.904

Bromine

Br

36

83.8

Krypton

Kr

37

85.4678

Rubidium

Rb

38

87.62

Strontium

Sr

39

88.9059

Yttrium

Y

40

91.224

Zirconium

Zr

41

92.9064

Niobium

Nb

42

95.94

Molybdenum

Mo

43

98

Technetium

Tc

44

101.07

Ruthenium

Ru

45

102.9055

Rhodium

Rh

46

106.42

Palladium

Pd

47

107.8682

Silver

Ag

48

112.411

Cadmium

Cd

49

114.818

Indium

In

50

118.71

Tin

Sn