An element X has mass number 35 and the number of neutrons is 18. Identify the group number and period of X.
An element X has mass number 35 and the number of neutrons is 18. Identify the group number and period of X.
1. As we know, the period number of an atom is equal to the number of shells inside the atom.
2. Therefore, first we have to calculate the atomic number then we get to know the number of shells present in it.
3. Step 1: Given that,
Mass number of element X is 35.
Number of neutrons = 18
As we know,
Mass number = Number of protons + Number of neutrons
35 = x + 18
x = 17
4. Step 2: As we know,
Atomic number = Number of protons = Number of electrons
∴ Number of electrons = 17
5. Hence, the electronic configuration of the element X is 2, 8, 7
6 From the electronic configuration, it can be seen that the chlorine atom has 3 shells, hence it belongs to period number 3.
Hence, Group of the element X = 17
Period of the element X = 3
1. As we know, the period number of an atom is equal to the number of shells inside the atom.
2. Therefore, first we have to calculate the atomic number then we get to know the number of shells present in it.
3. Step 1: Given that,
Mass number of element X is 35.
Number of neutrons = 18
As we know,
Mass number = Number of protons + Number of neutrons
35 = x + 18
x = 17
4. Step 2: As we know,
Atomic number = Number of protons = Number of electrons
∴ Number of electrons = 17
5. Hence, the electronic configuration of the element X is 2, 8, 7
6 From the electronic configuration, it can be seen that the chlorine atom has 3 shells, hence it belongs to period number 3.
Hence, Group of the element X = 17
Period of the element X = 3
