Excited State practice

Which of the following is the ground state configurations for an atom of magnesium?

• 2-8-2

• 2-8

• 2-7-1

• 2-8-1-1

Answer explanation

this configuration comes directly off the Periodic Table. 2-8-2.

This is for a neutral atom of Mg, since 12 total electrons will balance the charge of the 12 positive protons...

Also, your Periodic Table lists ground state (lowest energy state) configurations. So there is no further work to be done.

Tags

NGSS.HS-PS1-1

Which of the following is a valid ground state configuration for an atom of magnesium?

• 2-8-2

• 1-9-2

• 2-7-1

• 2-8-1-1

Answer explanation

Start with the ground state configurations for an atom of Mg, 2-8-2.

one of these electrons needs to move to a higher energy level (but we can't have 9 in the end shell... that's a rule violation)

2-8 is not enough total e- (that would be for an Mg²⁺ ion and in the ground state)

1-9-2 puts 9 in the 2nd shell, which isn't allowed.

2-8-2 is just the ground state, not excited.

only 2-8-1-1 works. A 3rd shell electron absorbs energy and jumps to the 4th shell.

Tags

NGSS.HS-PS1-1

Which of the following is a valid ground state configuration for a 2+ ion of magnesium?

• 2-8-2

• 1-9-2

• 2-7-1

• 2-8-1-1

Answer explanation

Start with the ground state configurations for an atom of Mg, 2-8-2. then alter it to be a 2+ ion. (Mg²⁺) It means we need to remove 2 e- so that there will be 2 more protons total than electrons. configuration is now 2-8.

2-8 would be the ground state for an Mg²⁺ ion.

We need one of the electrons to become excited and move to a higher level. one from the 2nd going up the 3rd is the easiest example. 2-7-1

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Write a valid excited state e- configuration for an atom of sulfur, S. (a)  

start with the ground state configurations, which is 2-8-6

Tags

NGSS.HS-PS1-1

Write a valid excited state e- configuration for the sulfide anion, S^2- (a)  

hints... start with the ground state configurations, which is 2-8-6

then, alter it based on charge of 2-

and ,finally, excite it from there,

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2