Question

In which pair do both atoms have one electron only in an s orbital in their ground states?

A Ca, Sc B Cu, Be C H, He D Li, Cr

what does electron in GROUND STATES means?
and what is the possible answer?

Answer 1

In their ground states, both Hydrogen (H) has one electron in the 1s orbital and Helium (He) has two electrons in a complete 1s orbital, making them the correct pair with only one electron in an s orbital. Thus, the answer is C. H, He.

Step-by-step explanation:

The question asks about atoms that have only one electron in an s orbital in their ground states. The term ground state refers to the lowest energy state of an atom, where the electrons are in the lowest available energy levels or orbitals. To determine which pair of atoms fits the criteria, we need to look at their electron configurations in the ground state.

Hydrogen (H) has one electron in the 1s orbital, making its electron configuration 1s¹. Helium (He) has two electrons in the 1s orbital, but since it is a completely filled shell, it is still considered in the ground state, with an electron configuration of 1s². Lithium (Li), on the other hand, has a 1s² 2s¹ configuration, with just one electron in the 2s orbital in its ground state. For the other atoms listed, such as Ca, Sc, Cu, Be, and Cr, they have more complex electron configurations with either more electrons in their outermost s orbitals or electrons in d orbitals in the case of transition metals.

Based on this information, the correct answer is C. H, He, because both hydrogen and helium have only one electron in their s orbital when they are in their ground states (even though helium has two electrons, they are in a complete s orbital).

Answer 2

The answer to this is letter D.

Chromium's electron configuration is 1s2 2s2 2p6 3s2 3p6 3d5 4s1, where the last electron is in the s orbital with only 1. As for Li, it is found in the group 1 metals, and it is a fact that all elements under this group has the their last electron to be in the s orbital with only one electron in their outermost shell.

The electron configuration associated with the lowest energy level of the atom is referred to as ground state and each electron ion is in the lowest energy level possible. When the moment comes that electrons go into a higher level of energy, that is what we call the excited state.