Atomic Number 1 To 30

Posted : admin On 1/3/2022
  1. Atomic Number Chart
  2. Atomic Number 30 Element
  3. Atomic Number 1 To 30 With Electronic Configuration
  4. Atomic Number 1 To 30

Atomic Weights of the Elements 2001, Pure Appl. 75(8), 1107-1122, 2003. Retrieved June 30, 2005. Atomic weights of elements with atomic numbers from 1-109 taken from this source. IUPAC Standard Atomic Weights Revised (2005). WebElements Periodic Table. Retrieved June 30, 2005. Atomic weights of elements with atomic numbers 110-116 taken.

  • Copper (Cu) Ar 3d 10 4s 1. Zinc (Zn) Ar 3d 10 4s 2. The electronic configuration of first 30.
  • Here is a list of the elements sorted by atomic number.Element nameElement symbolAtomic numberHydrogenH1HeliumHe2LithiumLi3.

How big is an atom? A simple question maybe, but the answer is not at all straighforward. To a first approximation we can regard atoms as 'hard spheres', with an outer radius defined by the outer electron orbitals. However, even for atoms of the same type, atomic radii can differ, depending on the oxidation state, the type of bonding and - especially important in crystals - the local coordination environment.

Take the humble carbon atom as an example: in most organic molecules a covalently-bonded carbon atom is around 1.5 Ångstroms in diameter (1 Ångstrom unit = 0.1 nanometres = 10-10 metres); but the same atom in an ionic crystal appears much smaller: around 0.6 Ångstroms. In the following article we'll explore a number of different sets of distinct atomic radius sizes, and later we'll see how you can make use of these 'preset' values with CrystalMaker.

Atomic Radii

Atomic radii represent the sizes of isolated, electrically-neutral atoms, unaffected by bonding topologies. The general trend is that atomic sizes increase as one moves downwards in the Periodic Table of the Elements, as electrons fill outer electron shells. Atomic radii decrease, however, as one moves from left to right, across the Periodic Table. Although more electrons are being added to atoms, they are at similar distances to the nucleus; and the increasing nuclear charge 'pulls' the electron clouds inwards, making the atomic radii smaller.

Atomic radii are generally calculated, using self-consistent field functions. CrystalMaker uses Atomic radii data from two sources:

  1. VFI Atomic Radii:
    Vainshtein BK, Fridkin VM, Indenbom VL (1995) Structure of Crystals (3rd Edition). Springer Verlag, Berlin.

  2. CPK Atomic Radii:
    Clementi E, Raimondi DL, Reinhardt WP (1963). Journal of Chemical Physics 38:2686-

Covalent Radii

The covalent radius of an atom can be determined by measuring bond lengths between pairs of covalently-bonded atoms: if the two atoms are of the same kind, then the covalent radius is simply one half of the bond length.

Whilst this is straightforward for some molecules such as Cl2 and O2, in other cases one has to infer the covalent radius by measuring bond distances to atoms whose radii are already known (e.g., a C--X bond, in which the radius of C is known).

CrystalMaker uses covalent radii listed on CrystalMaker-user Mark Winter's excellent Web Elements website.

Van-der-Waals Radii

Van-der-Waals radii are determined from the contact distances between unbonded atoms in touching molecules or atoms. CrystalMaker uses Van-der-Waals Radii data from:

Bondi A (1964) Journal of Physical Chemistry 68:441-

Atomic-Ionic Radii

These are the 'realistic' radii of atoms, measured from bond lengths in real crystals and molecules, and taking into account the fact that some atoms will be electrically charged. For example, the atomic-ionic radius of chlorine (Cl-) is larger than its atomic radius.

The bond length between atoms A and B is the sum of the atomic radii,

dAB = rA + rB

CrystalMaker uses Atomic-Ionic radii data from:

Slater JC (1964) Journal of Chemical Physics 39:3199-

Crystal Radii

Perhaps the most authoritative and highly-respected set of atomic radii are the 'Crystal' Radii published by Shannon and Prewitt (1969) - one of the most cited papers in all crystallography - with values later revised by Shannon (1976). These data, originally derived from studies of alkali halides, are appropriate for most inorganic structures, and provide the basis for CrystalMaker's default Element Table. The data are published in:

Shannon RD Prewitt CT (1969) Acta Crystallographica B25:925-946

Shannon RD (1976) Acta Crystallographica A23:751-761

The Colours of Atoms

Colour-coding atoms by element type is an important way of representing structural information. Of course, atoms don't have 'colour' in the conventional sense, but various conventions have been established in different disciplines.

Many organic chemists use the so-called CPK colour scheme These colours are derived from those of plastic spacefilling models developed by Corey, Pauling and (later improved on by) Kultun ('CPK').

Whilst the standard CPK colours are limited to the elements found in organic compounds, CrystalMaker's VFI Atomic Radii, CSD Default Radii and Shannon & Prewitt Crystal Radii Element Tables provide a more diverse range of contrasting colours.

Organic Structures Alert! CrystalMaker's default Element Table is the Shannon & Prewitt 'Crystal' radii, which is appropriate for most inorganic structures. When working with organic structures, one of the covalent or Van-der-Waals sets will be more appropriate.


  • Atomic number and Mass number
  • Isotopes


An atom is the smallest particle of an element which can take part in chemical reaction. Atom consists of three fundamental particles i.e. proton, neutron and electron. Atoms of same elements are similar in properties whereas atoms of different elements are different in properties. Example:- ‘H’ represent the atom of hydrogen.

Proton is positively charged and electron is negatively charged particle. In an atom, number of protons = number of electrons. Hence, the net charge present in an atom is zero i.e. a free atom is chargeless.

Atomic number and Mass number

Atomic number :
  • Atomic number is the number of protons present in an atom.
  • The modern periodic table is arranged in order of increasing atomic number.
Mass number and Atomic mass :
  • Mass number is the sum of the number of protons and the number of neutrons present in an atom. It is a whole number.

Mass no. of an atom = No. of protons + No. of neutrons

  • Atomic mass is the average mass of the all of the isotopes of that element. It is a decimal number.
  • For example: Hydrogen has three isotopes – 1H1, 1H2 and 1H3 having mass number 1, 2 and 3 respectively. Naturally occurring hydrogen contains about 99.985% of protium, 0.014% of deuterium and 0.001 % of tritium. Therefore the atomic mass of hydrogen is 1.00784 amu.
  • The atomic mass of an element element is measured in atomic mass unit (amu, also known as Daltons ‘ D’or unified atomic mass unit ‘u’).
  • 1amu = 1.66 x 10-24 grams. 1gm = 6.022 x 1023 amu ( i.e. Avogadro’s number).


  • Atomic number = Number of protons = Number of electrons = 13
  • Mass number = No. of protons + No. of neutrons
  • No. of neutrons = Mass number – No. of protons = 27-13 = 14.
Atomic mass of first 20 elements
Atomic numberElementAtomic mass


Atoms of the same element having same atomic number but different mass number (atomic mass/weight) are called isotopes. For example:

Isotopes of hydrogen :

There are three isotopes of hydrogen:

  1. Protium or ordinary hydrogen
  2. Deuterium or heavy hydrogen
  3. Tritium or radioactive hydrogen.
Name ProtiumDeuteriumTritium
Symbol1H or H2H or D3H or T
No. of protons(P)111
No. of neutrons(n)012
No. of electrons(e)111
Atomic no.(Z)111
Mass no.(A)123

Naturally occurring hydrogen contains about 99.985% of protium, 0.014% of deuterium and 0.001 % of tritium.

Isotopes have different physical properties since they differ in their mass number.

They have same chemical properties since their electronic configuration is same. However, they differ in the rate of chemical reaction. For example, D2 reacts with Cl2 about 13 times slower than H2 does. The different in rate of reaction due to difference in mass of the atoms of the same element is called isotope effect.

Some other examples of isotopic elements :

ElementsIsotopesMost abundant isotope
Carbon6C12, 6C13, 6C146C12
Nitrogen7N14, 7N157N14
Oxygen8O16, 8O17, 8O188O16
Sulphur16S32, 16S33, 16S34, 16S3616S32
Chlorine17Cl35, 17S3717Cl35


Atoms of different elements having different atomic number but same mass number are called isobars. For example :

18Ar40, 19K40 and 20Ca40


Atoms of different elements having different atomic number and mass number but same number of neutrons are called isotones. For example :

6C14, 7N15 and 8O16

Objective questions and their answers

1. Which of the following is known as heavy hydrogen?

a. Protium c. Tritium

b. Deuterium d. Para hydrogen

2. Which of the following is known as radioactive hydrogen?

a. Protium c. Tritium

b. Deuterium d. Para hydrogen

3. Least abundant isotope of hydrogen is:

a. Protium c. Tritium

b. Deuterium d. Heavy hydrogen

4. Diamond and graphite are :

Atomic Number Chart

a. Isotopes c. Isotones

b. Isobars d. Allotropes

5. 6C14 and 8O16 are :

a. Isotopes c. Isotones

b. Isobars d. Allotropes

6. 6C14 and 7N14 are :

a. Isotopes c. Isotones

b. Isobars d. Allotropes

Atomic Number 1 To 30Element with atomic number 17

7. All particles residing inside the nucleus of an atom are termed as:

Atomic Number 1 To 30

a. Protons c. Electrons

b. Neutrons d. Nucleons

Atomic Number 30 Element

8. What makes the atomic mass fractional ?

a.Prerence of isotopes

b. Number of unpaired electrons

c. Spherical shape

d. Quantum number.

9. Which of the following are not isotopes:

a. 1H1 and 1H3

b. 18K40 and 20Ca40

c. 6C14 and 7N14

d. Both b and c.

10. Charge present in the nucleus of an atom is :

a. Positive c. Chargeless

b. Negative d. Both +Ve and -Ve

Atomic Number 1 To 30 With Electronic Configuration

11. Molecular weight of heavy water is :

a. 16 c. 20

b. 18 d. 22

Answers :

Atomic Number 1 To 30

1. b 2. c 3. c

4. d [Note : different forms of same element having different properties are called allotropes]

5. c 6. b 7. d

8. a 9. d 10. a

11. c Note :Heavy waterDeuterium oxide (D2O) is called heavy water. It’s molecular weight is 20 and boiling paint is 101.50C and melting point is 3.80C.


  • Sthapit, M.K., Pradhananga, R.R., Foundations of Chemistry, Vol 1 and 2, Fourth edition, Taleju Prakashan, 2005.