Question

The size of the orbital is determined by the

Answer 1

Answer: The size of the orbital is determined by the principal quantum number, so the size of the orbital increases as this value increases. Therefore, an electron in a (n-1) orbital is closer to the nucleus than is an electron in a 'n' orbital.

Explanation:

In an atom, the position and energy of an electron is described by a set of numbers and these sets are called quantum numbers.  

There are four quantum numbers. These are as follows.

1). Principal quantum number - This is denoted by "n" and it determines the size and energy of shell in which electron is present. The value of "n" can be 1, 2, 3, and so on but it can never be equal to zero.

2). Azimuthal quantum number - This is denoted by "l" and it determines the shape of an orbital. For s, p, d and f-shell the values of "n" will be 0, 1, 2, 3. The value of l can vary from -n to +n.

3). Magnetic quantum number - This is denoted by "$m_{l}$." and it determines the orientation of an orbital. The value of ml can vary from -l to +l.

4). Spin quantum number -- This is denoted by "$m_{s}$" and it determines the spin of an electron. It is independent of the values of n, l and $m_{l}$.

This means that the size of an orbital is determined by principal quantum number. Lower is the value of 'n' (principal quantum number) more closer will be an electron to the nucleus. Hence, more is the value of 'n' more will be the size of nucleus and vice-versa.

For example, an electron present in a 2s-orbital is closer to the nucleus as compared to the electron present in a 3s-orbital.

Thus, we can conclude that the size of the orbital is determined by the principal quantum number, so the size of the orbital increases as this value increases. Therefore, an electron in a (n-1) orbital is closer to the nucleus than is an electron in a 'n' orbital.