Calculate the number of protons, neutrons and electrons in a species O 8 16 . What is the atomic number and mass number of this species?

According to the generalised representation of elements X Z A , A is the mass number and Z is the atomic number of element X. So, in this case, oxygen has mass number 16 and the atomic number is 8. The atomic number of an atom is nothing but the count of the total number of positive charges(protons) present in it. As the atomic number of oxygen is 8, the number of protons present in its atom is also 8. The mass number of oxygen is 16(given). Mass number (A) = total number of protons (Z) + total number of neutrons (N) Place the values 16 = 8 + N So , N = 16 - 8 N = 8 Atom is electrically neutral because it contains an equal number of positively charged protons and negatively charged electrons. So in oxygen Z= 8 (given) the number of electrons is also 8.

Composition of the nuclei of two species X and Y are given as follows: Species X Y Protons 6 6 Neutrons 6 7 Give the mass numbers of X and Y. What is the relation between the two species?

The formula to find the mass number is A = Z + N where A is the mass number, Z is the atomic number which is equal to the total number of protons and N is equal to the total number of neutrons. The mass number of X = 6 + 6 = 12 The mass number of Y = 6 + 7 = 13 These two species are the atoms of the same element as they both have the same atomic number with different mass numbers. Hence, they both are isotopes of the same element that is carbon.

E M B I B E

Secondary Chemistry>Chapter 4 - Structure of Atom>Questions as per the Guidelines of CBSE>Q 5

MEDIUM

9th CBSE

IMPORTANT

Earn 100

Write the electronic configuration of oxygen and name its valence shell (atomic number of O is 8).

Important Questions on Structure of Atom

EASY

9th CBSE

IMPORTANT

Secondary Chemistry>Chapter 4 - Structure of Atom>Questions as per the Guidelines of CBSE>Q 6

What is the rule that provides the electron capacity of an energy shell and calculate the maximum number of electrons which can be assigned to the M-energy shell of an atom.