Atomic number of Ag is 47. In the same group the atomic number of elements placed above and below Ag will be
Atomic number of Ag is 47. In the same group the atomic number of elements placed above and below Ag will be
The correct option is B 29, 79
Let's look at the electronic configuration of Ag which is [Kr]4d10 5s1. From the electronic configuration, we can infer that the element belongs to the 5th period because there are five shells in the atom.
In 4th and 5th periods there are 18 elements each in the periodic table. Therefore atomic numbers of the element placed above Ag and in the same group differ by 18. Hence the atomic number of the element above Ag is 47-18 = 29. The atomic number of below element will differ by 32 because there are Lanthanides (14) along with other 18 elements in the 6th period.
Hence the atomic numbers of the elements above and below Ag in the same group respectively are 29 and 79.
Shortcut:
Again, the concept of magic numbers is valid: 2, 8, 8, 18, 18, 32 and so on. You only need to know to which period the element belongs. In this case, we figured out that the element is in the 5th period. The 5th number in our series is 18. So, element previous would be 47 - 18, and next element would be 47 + 32.
29, 79
Let's look at the electronic configuration of Ag which is [Kr]4d10 5s1. From the electronic configuration, we can infer that the element belongs to the 5th period because there are five shells in the atom.
In 4th and 5th periods there are 18 elements each in the periodic table. Therefore atomic numbers of the element placed above Ag and in the same group differ by 18. Hence the atomic number of the element above Ag is 47-18 = 29. The atomic number of below element will differ by 32 because there are Lanthanides (14) along with other 18 elements in the 6th period.
Hence the atomic numbers of the elements above and below Ag in the same group respectively are 29 and 79.
Shortcut:
Again, the concept of magic numbers is valid: 2, 8, 8, 18, 18, 32 and so on. You only need to know to which period the element belongs. In this case, we figured out that the element is in the 5th period. The 5th number in our series is 18. So, element previous would be 47 - 18, and next element would be 47 + 32.
