Atomic Number and Mass Number of First 30 Elements (2024)

What is Mass Number? The answer to this question and other informative content related to molecular chemistry is provided here. Read this article to get the basic knowledge of the atomic number and atomic mass of elements.

Atomic Number and Mass Number of Elements: Atoms are the building blocks of matter. They are responsible for the format of all living and non-living things. Understanding their molecular structure and terminologies is the initial step to learning chemistry. Two important concepts in atomic structure are the atomic number and the mass number. Let’s explore what these terms mean and how they are used.

What is Atomic Number?

  • The atomic number is a fundamental property of an atom. It is defined as the number of protons found in the nucleus of an atom.
  • It is represented by the symbol ‘Z’.
  • Atoms of the same atomic number and chemical properties combine to form an element.
  • Different elements are formed by different types of atoms.

Formula for Atomic Number

Calculating atomic number is simple. The number of protons in an atom is the direct math to know the atomic number. Thus, the formula for atomic number would be:

Atomic Number (Z)=Number of Protons

Example:

  • Hydrogen: The simplest atom, hydrogen, has 1 proton in its nucleus. Therefore, the atomic number of hydrogen is 1.
  • Carbon: Carbon atoms have 6 protons. Thus, the atomic number of carbon is 6.

Every element on the periodic table has a unique atomic number. This number is usually written above the element symbol on the periodic table.

What is Mass Number?

  • The mass number is called the atomic mass number of nuclear number.
  • The atomic mass number is the total number of protons and neutrons in an atom’s nucleus.
  • It is represented by the symbol ‘u’ (earlier abbreviated as ‘amu’, but according to th latest IUPAC recommendations, it is now written as ‘u’ – unified mass).
  • Neutrons are neutral particles, meaning they have no charge, but they add to the mass of an atom along with protons.

Formula for Atomic Mass Number

The calculation of atomic mass is easy. Just add the number of protons and neutrons of an atom to get its atomic mass. Thus, the formula for atomic mass would be:

Mass Number (u)=(Number of Protons)+(Number of Neutrons)

Or,

Mass Number (u)=(Atomic Number)+(Number of Neutrons)

Example:

  • Hydrogen: Most hydrogen atoms have 1 proton and 0 neutrons, so the mass number of hydrogen is 1.
  • Carbon: A common form of carbon has 6 protons and 6 neutrons. Thus, the mass number of this carbon atom is 12.

The mass number is not listed on the periodic table because it can vary for different atoms of the same element, known as isotopes.

Isotopes

Isotopes are atoms of the same element that have same atomic number but varies in atomic masses due to the difference in their numbers of neutrons.

Example:

Carbon Isotopes:

  • Carbon-12 has 6 protons and 6 neutrons (mass number = 12).
  • Carbon-14 has 6 protons and 8 neutrons (mass number = 14).

Calculating Atomic Number

Example 1: Oxygen

Oxygen is a common element found in the air we breathe. To find its atomic number:

  • Look at the periodic table and find oxygen (O).
  • The atomic number of oxygen is listed as 8.
  • This means oxygen has 8 protons in its nucleus.

Example 2: Sodium

Sodium is a metal commonly found in table salt. To find its atomic number:

  • Look at the periodic table and find sodium (Na).
  • The atomic number of sodium is listed as 11.
  • This means sodium has 11 protons in its nucleus.

Calculating Mass Number

Example 1: Chlorine

Chlorine is often used in cleaning products. To calculate its mass number:

  • Chlorine atoms typically have 17 protons.
  • A common isotope of chlorine has 18 neutrons.
  • Using the formula:

Mass Number=Number of Protons+Number of Neutrons

Mass Number=17+18=35

So, the mass number of this chlorine isotope is 35.

Example 2: Potassium

Potassium is an essential nutrient for plants and animals. To calculate its mass number:

  • Potassium atoms typically have 19 protons.
  • A common isotope of potassium has 20 neutrons.
  • Using the formula:

Mass Number=Number of Protons+Number of Neutrons

Mass Number=19+20=39

So, the mass number of this potassium isotope is 39.

Atomic Number and Mass Number of First 30 Elements

Students are generally advised to memorise the first 30 elements from the periodic table. And thus, expected to be aware of the atomic number and the atomic mass of those 30 elements. Here, the list of those 30 elements are provided along with atomic number, atomic mass, name and symbol.

Atomic Number (Z)

Element Name

Symbol

Atomic Mass (u)

1

Hydrogen

H

1.008

2

Helium

He

4.0026

3

Lithium

Li

6.94

4

Beryllium

Be

9.0122

5

Boron

B

10.81

6

Carbon

C

12.011

7

Nitrogen

N

14.007

8

Oxygen

O

15.999

9

Fluorine

F

18.998

10

Neon

Ne

20.18

11

Sodium

Na

22.99

12

Magnesium

Mg

24.305

13

Aluminum

Al

26.982

14

Silicon

Si

28.085

15

Phosphorus

P

30.974

16

Sulfur

S

32.06

17

Chlorine

Cl

35.45

18

Argon

Ar

39.948

19

Potassium

K

39.098

20

Calcium

Ca

40.078

21

Scandium

Sc

44.956

22

Titanium

Ti

47.867

23

Vanadium

V

50.942

24

Chromium

Cr

51.996

25

Manganese

Mn

54.938

26

Iron

Fe

55.845

27

Cobalt

Co

58.933

28

Nickel

Ni

58.693

29

Copper

Cu

63.546

30

Zinc

Zn

65.38

Hopefully this article helped to understand the basics of molecular chemistry. To get for such information check the links below:

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  • CBSE Class 12 Electric Charges and Fields Formula List: Download PDF
  • CBSE Class 12th Chemistry Notes (Based on NCERT Textbook): All Chapters
  • Important Chemical Reactions for Class 12 Chemistry
Atomic Number and Mass Number of First 30 Elements (2024)

FAQs

What is the atomic mass number of first 30 elements? ›

Atomic Mass of First 30 Elements
ATOMIC NUMBERELEMENTATOMIC MASS
1Hydrogen1.008
2Helium4.0026
3Lithium6.94
4Beryllium9.0122
26 more rows

What is the atomic mass and mass number of elements? ›

Atomic Number and Mass Number

While the mass number is the sum of the protons and neutrons in an atom, the atomic number is only the number of protons. The atomic number is the value found associated with an element on the periodic table because it is the key to the element's identity.

How to learn 1 to 30 atomic number? ›

If we are talking about the first 30 elements then the periodic table starts with Hydrogen and ends at Zinc that is an element with atomic number 30. These elements can be remembered by this line: Harley Health Like Beautiful Body of Cheetah Name Opposite Falcon Nest.

How to find mass number? ›

The mass number is defined as the total number of protons and neutrons in an atom. It can be calculated by adding the number of neutrons and the number of protons (atomic number) together.

What is the atomic mass for each element? ›

Tabular Atomic Mass Data
Atomic NumberSymbolAtomic Mass [u]
6C12.011
7N14.007
8O15.999
9F18.99840316
110 more rows

What is the easiest way to memorize atomic mass? ›

For starters, the easiest and the most used trick to remember the atomic masses is to multiply the atomic number by 2.

What is the easiest way to find the atomic number? ›

The total number of protons in the nucleus of an atom gives us the atomic number of that atom.

What element has 28 mass number? ›

#28 - Nickel - Ni.

What elements have an atomic mass from 30 to 40? ›

List of Chemical Elements
Atomic NumberAtomic MassChemical Element Name
3065.39Zinc
3169.723Gallium
3272.64Germanium
3374.9216Arsenic
56 more rows

What element has 32 mass number? ›

Sulphur

Is P atomic mass 30 or 31? ›

Phosphorus has an atomic mass of 30.97 amu (atomic mass unit). Phosphorus has a molar mass of 123.88 g/mol and is a chemical element. Phosphorus is a chemical element with the symbol P and the atomic number 15.

What is the atomic mass of 1 to 50 elements? ›

Atomic Number of Elements from 1 to 50
Atomic NumberChemical SymbolAtomic Weight (u)
4Be9.0121831
5B10.81
6C12.011
7N14.007
46 more rows

What is the mass number of an atom that contains 30 protons 30 electrons and 35 neutrons? ›

The mass number of an element that has 30 protons, 35 neutrons and 30 electrons will be 65.

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