Exam Questions and correct
Answers 2025
1. What is the atomic number of oxygens?
A. 6
B. 8
C. 10
D. 16
2. Which subatomic particle has a negative charge?
A. Proton
B. Neutron
C. Electron
D. Ion
3. What is the pH of a neutral solution?
A. 0
B. 3
C. 7
D. 14
,4. What type of bond is formed when electrons are shared between atoms?
A. Ionic bond
B. Hydrogen bond
C. Covalent bond
D. Metallic bond
5. Which state of matter has a definite volume but no definite shape?
A. Solid
B. Liquid
C. Gas
D. Plasma
6. Which of the following elements is a noble gas?
A. Oxygen
B. Argon
C. Hydrogen
D. Nitrogen
7. What is the formula for sulfuric acid?
A. HCl
B. H₂SO₄
C. HNO₃
D. H₂CO₃
8. What is the molar mass of water (H₂O)?
A. 10 g/mol
B. 15 g/mol
C. 18 g/mol
D. 20 g/mol
, 9. Which temperature is the freezing point of water in Celsius?
A. 100°C
B. 0°C
C. 32°C
D. -273°C
10. What type of reaction is this: 2H₂ + O₂ → 2H₂O?
A. Decomposition
B. Synthesis
C. Single replacement
D. Double replacement
11. Which element has the atomic symbol "Na"?
A. Nitrogen
B. Sodium
C. Neon
D. Nickel
12. What is the charge of a proton?
A. Neutral
B. Positive
C. Negative
D. Variable
13. How many valence electrons does carbon have?
A. 2
B. 4
C. 4
D. 6