1. How many valence electrons does a hydrogen atom have?
A.
0
B.
1
C.
2
D.
7
Correct Answer:
1
Explanation:
Hydrogen has only one electron, located in its outermost and only occupied shell. Thus, it has one valence electron.
2. What is the electronic configuration of the hydrogen ion H⁺?
A.
1s¹
B.
1s²
C.
2s¹
D.
No electrons
Correct Answer:
No electrons
Explanation:
A hydrogen atom has one electron. When it forms H⁺ by losing that electron, no electrons remain.
3. What is the electronic configuration of the hydride ion, H⁻?
A.
1s⁰
B.
1s¹
C.
1s²
D.
2s²
Correct Answer:
1s²
Explanation:
A hydride ion is formed when a hydrogen atom gains one electron. It therefore has two electrons, both occupying the 1s orbital.
4. Which statement about the hydrogen atom's electronic configuration 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 2p orbital.
D.
It has two electrons in the 2s orbital.
Correct Answer:
It has one electron in the 1s orbital.
Explanation:
The ground-state hydrogen atom contains one electron, and that electron occupies the 1s orbital.
5. Which orbital notation represents the ground-state electronic configuration of hydrogen?
A.
1s: ↑
B.
1s: ↑↓
C.
2s: ↑
D.
2p: ↑
Correct Answer:
1s: ↑
Explanation:
Hydrogen has one electron in the 1s orbital. The upward arrow represents this single electron.
6. The electronic configuration 1s¹ represents which species?
A.
A neutral hydrogen atom
B.
A hydrogen ion, H⁺
C.
A hydride ion, H⁻
D.
A helium atom
Correct Answer:
A neutral hydrogen atom
Explanation:
The configuration 1s¹ contains one electron, which corresponds to a neutral hydrogen atom.
7. Which species has the same number of electrons in the 1s orbital as a helium atom?
A.
H⁺
B.
H
C.
H⁻
D.
A hydrogen atom with configuration 2s¹
Correct Answer:
H⁻
Explanation:
A helium atom has two electrons with configuration 1s². The hydride ion, H⁻, also has two electrons in the 1s orbital.
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