Which of the following electron configurations describes an element that is a noble gas?
a. 1s22s22p4

b. [ne]2s22p2

c. [ar] 3s1

d. 1s22s22p6

The answer to your question is: letter D.

Explanation:

Noble gases are located in group VIIIA of the periodic table, this means that they have 8 eight electrons in their outermost shell.

Due to this characteristic, they are stable and do not react with other elements.

a. 1s22s22p4    The outermost shell of this electron configuration has 6 electrons, then this element has 6 electrons not 8. This configuration is of an element of the group VIA.

b. [Ne]2s22p2  The outermost shell of this element has 4 electrons, so this is not the configuration of a noble gas.

c. [Ar] 3s1  This element only has one electron in its outermost shell, so this is the electron configuration of an alkaline metal.

d. 1s22s22p6 This element has 8 electrons in its outermost shell, so this is the electron configuration of a noble gas.

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hope that

the answer would be a