Question

The chemical symbol of several elements are given below. Determine the atomic number of each element. Chemical Atomic Number Symbol Number Fe Number Be Number Number Kr Determine the number of protons, neutrons, and electrons present in each of the following atoms Protons Neutrons Electrons Number Number Number 53 Cr Number Number Number 103 Ru Number Number Number Number Number 67 Zn Using the periodic table, identily the name and symbol of the folowing three neutral atoms given their atomic numbers and masses. Remember, spelling counts. Atomic Number Mass Number Atomic Symbol Replace each question mark with the appropriate integer or element symbol. Element Name 14 28 18 40 19 39

Answer 1

Explanation:

Atomic number is defined as the number of protons or electrons that are present in a neutral atom.

Atomic number = number of protons = number of electrons

Mass number is defined as the sum of number of protons and neutrons that are present in an atom.

Mass number = Number of protons + Number of neutrons

The isotopic representation of an atom is: $_Z^A\textrm{X}$

where,

Z = Atomic number of the atom

A = Mass number of the atom

X = Symbol of the atom

• For A:

1) Fe

The atom given to us is iron. It is present in Group 8 and period 4 of the periodic table. The atomic number of iron is 26

2) Be

The atom given to us is beryllium. It is present in Group 2 and period 2 of the periodic table. The atomic number of beryllium is 4

3) Kr

The atom given to us is krypton. It is present in Group 18 and period 4 of the periodic table. The atomic number of iron is 36

• For B:

1) $_{24}^{53}\textrm{Cr}$

Atomic number = Number of protons = Number of electrons = 24

Mass number = 53

Number of neutrons = 53 - 24 = 29

The number of protons, electrons and neutrons for the given element are 24, 24 and 29 respectively

2) $_{44}^{103}\textrm{Ru}$

Atomic number = Number of protons = Number of electrons = 44

Mass number = 103

Number of neutrons = 103 - 44 = 59

The number of protons, electrons and neutrons for the given element are 44, 44 and 59 respectively

3) $_{30}^{67}\textrm{Zn}$

Atomic number = Number of protons = Number of electrons = 30

Mass number = 67

Number of neutrons = 67 - 30 = 37

The number of protons, electrons and neutrons for the given element are 30, 30 and 37 respectively

• For C:

1) Atomic number = 14; Mass number = 28

The element having atomic number '14' is Silicon

The isotopic symbol of the element is $_{14}^{28}\textrm{Si}$

The symbol of the element is 'Si'

2) Atomic number = 18; Mass number = 40

The element having atomic number '18' is Argon

The isotopic symbol of the element is $_{18}^{40}\textrm{Ar}$

The symbol of the element is 'Ar'

3) Atomic number = 19; Mass number = 39

The element having atomic number '19' is Potassium

The isotopic symbol of the element is $_{19}^{39}\textrm{K}$

The symbol of the element is 'K'