Question
Use these answers for questions 4 - 7.
(A) 1s2 2s22p5 3s23p5
(B) 1s2 2s22p6 3s23p6
(C) 1s2 2s22p62d10 3s23p6
(D) 1s2 2s22p6 3s23p63d5
(E) 1s2 2s22p6 3s23p63d3 4s2
4. An impossible electronic configuration
5. The ground-state configuration for the atoms of a transition element
6. The ground-state configuration of a negative ion of a halogen
7. The ground-state configuration of a common ion of an alkaline earth element
Electron configurations really confuse me. How come E goes from 3d3 to 4s2? I need help with #6 & 7. I don't understand what they're asking or how to figure them out. This is a very weak area for me!
For #6, all of the halogens are in group 17 (VIIA depending upon the system you are using). Therefore, they have a ns2, np5 configuration (note 7 electrons in the outside shell) where n is 2, 3, 4, 5 etc depending upon the particular halogen we are discussing. They become the -1 ion by adding an electron to the p level to make the outside shell ns2, np6.
For #7, all alkaline earths are in group 2 (or IIA) and have a ns2 configuration. If they lose those two electrons, their electronic configuration becomes that of the noble gas two elements below it; for example, <sub>12</sub>Mg is 1s2 2s2 2p6 3s2 (12 total). Losing those two electrons makes it 1s2 2s2 2p6 (total 10) which makes it like Ne (12-10=2 elements below Mg).
(A) 1s2 2s22p5 3s23p5
(B) 1s2 2s22p6 3s23p6
(C) 1s2 2s22p62d10 3s23p6
(D) 1s2 2s22p6 3s23p63d5
(E) 1s2 2s22p6 3s23p63d3 4s2
4. An impossible electronic configuration
5. The ground-state configuration for the atoms of a transition element
6. The ground-state configuration of a negative ion of a halogen
7. The ground-state configuration of a common ion of an alkaline earth element
Electron configurations really confuse me. How come E goes from 3d3 to 4s2? I need help with #6 & 7. I don't understand what they're asking or how to figure them out. This is a very weak area for me!
For #6, all of the halogens are in group 17 (VIIA depending upon the system you are using). Therefore, they have a ns2, np5 configuration (note 7 electrons in the outside shell) where n is 2, 3, 4, 5 etc depending upon the particular halogen we are discussing. They become the -1 ion by adding an electron to the p level to make the outside shell ns2, np6.
For #7, all alkaline earths are in group 2 (or IIA) and have a ns2 configuration. If they lose those two electrons, their electronic configuration becomes that of the noble gas two elements below it; for example, <sub>12</sub>Mg is 1s2 2s2 2p6 3s2 (12 total). Losing those two electrons makes it 1s2 2s2 2p6 (total 10) which makes it like Ne (12-10=2 elements below Mg).
Answers
Bot
Therefore, the answers to #6 and #7 are (B) and (E) respectively.