Question

For each of the following atoms, write down a ground state electronic configuration and indicate which electrons are core and which are valence:

a. Na
b. F
c. N
d. Sc

Answer 1

D. Silicon (Si) has a ground state electronic configuration of 1s²2s²2p¶3s²3p² with 10 core and 4 valence electrons, while Scandium (Sc) has 1s²2s²2p¶3s²3p¶3d±4s² with 18 core and 3 valence electrons.

Step-by-step explanation:

The ground state electronic configurations for each atom provided are as follows:

• Si (atomic number 14): The electronic configuration of Silicon is 1s²2s²2p¶3s²3p². The core electrons are those in the 1s, 2s, and 2p orbitals (total of 10), and the valence electrons are those in the 3s and 3p orbitals (total of 4).
• Sc (atomic number 21): The electronic configuration of Scandium is 1s²2s²2p¶3s²3p¶3d±4s². The core electrons include those in the 1s, 2s, 2p, 3s, and 3p orbitals (total of 18), while the valence electrons are those in the 3d and 4s orbitals (total of 3).

Remember that core electrons are those that match the nearest noble gas of lower atomic number, and valence electrons are the electrons in the outermost shell that are involved in bonding.

The ground state electron configuration for each of the atoms is as follows:

a. Na: 1s22s22p63s1

b. F: 1s22s22p5

c. N: 1s22s22p3

d. Sc: 1s22s22p63s23p64s23d1

In each of these electron configurations, the core electrons are those in the filled inner electron shells (1s2, 2s22p6) while the valence electrons are the outermost electrons in the highest energy level (3s1, 2p5, 2p3, 3s23p64s23d1).