An element with the general electron configuration

18. An element with the general electron configuration for its outermost electrons of ns
2
np
1
would be in
which element group?
A) 2A B) 3A C) 4A D) 5A
Ans: B
E) 8A
19. In what row and group of the periodic table would you find the element with the electron configuration
[Kr]5s 2 4d 10 5p 2 ?
20. Consider the element with the electron configuration [Kr]5s 2 4d 7 . This element is 21. Consider the element with the electron configuration [Kr]5s 2 4d 10 5p 5 . This element is

23. The representative elements are those with unfilled energy levels in which the "last electron" was added
to
A) an s orbital. D) a p or d orbital.
B) an s or p orbital. E) an f orbital.
C) a d orbital.
Ans: B
24. How many valence electrons does S 2- have?
16 E) 8
25. How many valence electrons does P 3- have?
1 E) 18
26. How many electrons does a sulfur atom need to fill its outermost s and p subshells?
2 E) 1
27. How many electrons does a nitrogen atom need to fill its outermost s and p subshells?
A) 5 B) 3 C) 1 D)
Ans: B
8 E) 0
28. How many electrons does a bromine atom need to fill its outermost s and p subshells?
3 E) 1
31. How many core electrons does a chlorine atom have?
18 E) 8
32. How many core electrons does a silicon atom have?
8 E) 2
33. Concerning the electron configuration of fluorine, 1s
2
2s
2
2p
5
which of the following represents the core
electrons only?
A) 1s
2
B) 1s
2
2s
2
C) 1s
2
2s
2
2p
5
D) 2s
2
2p
5
E)
Ans: A
2p
5
34. Concerning the electron configuration of sulfur, 1s 2 2s 2 2p 6 3s 2 3p 4 , which of the following represents the
core electrons only?
3p 4
35. Concerning the electron configuration of aluminum, 1s 2 2s 2 2p 6 3s 2 3p 1 , which of the following represents
the valence electrons only?
3p 1

36. Which one of the following elements forms a stable 3- anion?
E) Mg