1. What is the atomic number of hydrogen?
A.
1
B.
2
C.
6
D.
8
Correct Answer:
1
Explanation:
Hydrogen has one proton in its nucleus, so its atomic number is 1.
2. The atomic number of an element represents the number of which particles in its nucleus?
A.
Neutrons
B.
Protons
C.
Electrons only
D.
Molecules
Correct Answer:
Protons
Explanation:
Atomic number is defined as the number of protons present in the nucleus of an atom.
3. A neutral hydrogen atom has an atomic number of 1. How many electrons does it have?
A.
0
B.
1
C.
2
D.
3
Correct Answer:
1
Explanation:
In a neutral atom, the number of electrons equals the atomic number, which is 1 for hydrogen.
4. Which symbol correctly represents the atomic number of hydrogen?
A.
Z = 1
B.
Z = 2
C.
A = 1
D.
A = 2
Correct Answer:
Z = 1
Explanation:
The atomic number is represented by Z, and hydrogen has one proton; therefore, Z = 1.
5. An atom has one proton in its nucleus. Which element is it?
A.
Helium
B.
Hydrogen
C.
Lithium
D.
Carbon
Correct Answer:
Hydrogen
Explanation:
An element with one proton has atomic number 1, which identifies it as hydrogen.
6. Which of the following is the correct atomic number of hydrogen in the periodic table?
A.
0
B.
1
C.
7
D.
17
Correct Answer:
1
Explanation:
Hydrogen is the first element in the periodic table because its atomic number is 1.
7. If the atomic number of an atom is 1, how many protons does its nucleus contain?
A.
1
B.
2
C.
6
D.
8
Correct Answer:
1
Explanation:
The atomic number directly equals the number of protons, so an atomic number of 1 means one proton.
8. Which element has atomic number 1?
A.
Hydrogen
B.
Helium
C.
Oxygen
D.
Nitrogen
Correct Answer:
Hydrogen
Explanation:
Hydrogen is assigned atomic number 1 because each hydrogen atom contains one proton.
9. What determines that an atom belongs to hydrogen rather than another element?
A.
Its number of protons
B.
Its number of neutrons only
C.
Its physical state only
D.
Its number of molecules
Correct Answer:
Its number of protons
Explanation:
The number of protons, called the atomic number, identifies the element. Hydrogen has one proton.
10. Which statement about hydrogen's atomic number is correct?
A.
It is equal to 1
B.
It is equal to 2
C.
It is equal to the number of neutrons in every hydrogen atom
D.
It changes when hydrogen is converted into a gas
Correct Answer:
It is equal to 1
Explanation:
Hydrogen always has atomic number 1 because its nucleus contains one proton, regardless of its physical state.
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