Complete the following table: X 23 11 Atomic number _____ Mass number _____ Number of electrons _____ Number of Protons _____ Number of neutrons _____

Given element is: X 23 11 Atomic number = 11 Mass number = 23 Number of electrons = number of protons = atomic number = 11 Number of Protons = atomic number = 11 Number of neutrons = 23 - 11 = 12

Complete the following table: Y 40 20 Atomic number _____ Mass number _____ Number of electrons _____ Number of Protons _____ Number of neutrons _____

Given element is: Y 40 20 Atomic number = 20 Mass number = 40 Number of electrons = number of protons = atomic number = 20 Number of Protons = atomic number = 20 Number of neutrons = 40 - 20 = 20

Complete the following table: Valence electrons 1 2 3 4 5 6 7 8 Valency Metal/Non-metal

The number of electrons that must be lost or gained by an atom to obtain a stable electron configuration is known as valency of that element. Valence electrons 1 2 3 4 5 6 7 8 Valency + 1 + 2 + 3 + 4 / - 4 - 3 - 2 - 1 0 Metal/Non-metal Metal Metal Metal Non-metal Non-metal Non-metal Non-metal Non-metal

Draw structure from the following information: An atom has a mass number 16 and a number of protons equal to 8 . Structure: Symbol:

The atomic number is equal to the number of protons, so the atomic number of the element is 8 . The mass number given is 16 , the mass number is the sum of no. of protons and neutrons. Hence, the structure of a given element i.e. oxygen is given below. The symbol of oxygen is O 16 8 .