Question

The electron configuration of an element is 1s^22s^1. How many valence electrons does the element have?

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Answer 1

The element has 1 valence electron.

Step-by-step explanation:

The electron configuration of an element is 1s22s1. To determine the number of valence electrons, we look at the highest energy level, which is indicated by the last number in the electron configuration. In this case, the highest energy level is the 2s level. Therefore, the element has 1 valence electron.

Answer 2

Answer : The number of valence electron present in an element is, 1

Explanation :

Electronic configuration : It is defined as the representation of electrons around the nucleus of an atom.

Number of electrons in an atom are determined by the electronic configuration.

Atomic number : It is defined as the number of electrons or number of protons present in a neutral atom.

The given electronic configuration of an element is,

`1s^22s^1`

That means, the element has 1 valence electrons.