1. How many electrons are present in a neutral hydrogen atom?
A.
0
B.
1
C.
2
D.
3
Correct Answer:
1
Explanation:
Hydrogen has atomic number 1, so a neutral hydrogen atom contains one electron.
2. Which shell contains the electron of a ground-state hydrogen atom?
A.
K shell
B.
L shell
C.
M shell
D.
N shell
Correct Answer:
K shell
Explanation:
The hydrogen electron occupies the first energy level, which is called the K shell.
3. What is the number of valence electrons in a hydrogen atom?
A.
0
B.
1
C.
2
D.
7
Correct Answer:
1
Explanation:
Hydrogen has one electron, and it is present in its outermost and only occupied shell.
4. Which orbital is occupied by the electron in ground-state hydrogen?
A.
1s
B.
2s
C.
2p
D.
3s
Correct Answer:
1s
Explanation:
The single electron of hydrogen occupies the lowest-energy 1s orbital in the ground state.
5. What is the electronic configuration of the hydride ion H−?
A.
1s1
B.
1s2
C.
2s1
D.
2p2
Correct Answer:
1s2
Explanation:
The hydride ion has gained one electron, giving it two electrons arranged as 1s2.
6. Which statement about the electronic configuration of hydrogen is correct?
A.
It has two electrons in the 1s orbital.
B.
It has one electron in the 1s orbital.
C.
It has one electron in the 2s orbital.
D.
It has one electron in the 2p orbital.
Correct Answer:
It has one electron in the 1s orbital.
Explanation:
The ground-state configuration of hydrogen is 1s1, meaning one electron is present in the 1s orbital.
7. The electronic configuration 1s1 represents which species?
A.
A neutral hydrogen atom
B.
A helium atom
C.
A hydrogen ion H+
D.
A hydride ion H−
Correct Answer:
A neutral hydrogen atom
Explanation:
The configuration 1s1 contains one electron, corresponding to a neutral hydrogen atom.
8. How many electrons are required for hydrogen to attain the helium-like configuration 1s2?
A.
It must lose one electron.
B.
It must gain one electron.
C.
It must gain two electrons.
D.
It must lose two electrons.
Correct Answer:
It must gain one electron.
Explanation:
Hydrogen starts with one electron, so gaining one electron gives it the 1s2 configuration.
9. What is the electronic configuration of a neutral hydrogen atom in its ground state?
A.
1s¹
B.
1s²
C.
2s¹
D.
2p¹
Correct Answer:
1s¹
Explanation:
A neutral hydrogen atom has one electron, which occupies the lowest-energy 1s orbital in the ground state.
10. How many electrons are present in a neutral hydrogen atom?
A.
0
B.
1
C.
2
D.
3
Correct Answer:
1
Explanation:
Hydrogen has atomic number 1, so a neutral hydrogen atom contains one electron.
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