Question

He image shows the representation of an unknown element in the periodic table.

Answer 1

Answer:

the number of neutrons in an atom of the element is 10.

Explanation:

neutron: mass # -protons

neutron: 19 (18.9984 (rounded)) - 9

neutron: 19- 9 =10

whole number is equal to the number of protons.

Answer 2

Answer: Option (b) is the correct answer.

Explanation:

Atomic number is the sum of total number of protons present in an atom. And, atomic mass is the sum of total number of protons and neutrons present in an element.

Also, in a neutral atom the number of protons equal to the number of electrons.

Generally, atomic number is written on the top right corner of the symbol of an element and atomic mass is written at the bottom.

So here, number 9 is the atomic number and its atomic mass will be approximately 19.

Therefore, number of neutrons present in the given element will be as follows.

                    Atomic mass = no. of protons + no. of neutrons

                              19 = 9 + no. of neutrons

                        no. of neutrons = 19 - 9

                                                 = 10

Thus, we can conclude that the statement number of neutrons in an atom of the element is 10, is true.