(a) What is meant by (i) atomic number, and (ii) mass number, of an el

1.	(a) What is meant by (i) atomic number, and (ii) mass number, of an element? Explain with the help of an example. (b) What is the relation between the atomic number and mass number of an element? (c) If an element M has mass number 24 and atomic number 12, how many neutrons does its atom contain?
Answer» (a) Atomic no. is the number of protons in one atom of an element. Mass no. is the total number of protons and neutrons present in one atom of the element. Example- The total no. of protons in a carbon atom is 6, so its atomic no. is 6. Also, one atom of Na contains 11 protons and 12 neutrons, so its mass no. is 23. (b). Mass No. = Atomic no. + No. of neutrons (c). No. of neutrons = Mass No. – Atomic no. = 24 – 12 = 12

(a) What is meant by (i) atomic number, and (ii) mass number, of an element? Explain with the help of an example. (b) What is the relation between the atomic number and mass number of an element? (c) If an element M has mass number 24 and atomic number 12, how many neutrons does its atom contain?

Answer»

(a) Atomic no. is the number of protons in one atom of an element.

Mass no. is the total number of protons and neutrons present in one atom of the element.

Example- The total no. of protons in a carbon atom is 6, so its atomic no. is 6.

Also, one atom of Na contains 11 protons and 12 neutrons, so its mass no. is 23.

(b). Mass No. = Atomic no. + No. of neutrons

(c). No. of neutrons = Mass No. – Atomic no.

= 24 – 12 = 12