Picat General Science 2 — Questions and Answers
Question 1: What is the atomic number of carbon?
- 4
- 6 (Correct answer)
- 8
- 12
Correct answer: 6
Carbon has 6 protons in its nucleus, giving it an atomic number of 6.
Question 2: Which type of chemical bond involves the sharing of electrons between atoms?
- Ionic bond
- Hydrogen bond
- Covalent bond (Correct answer)
- Metallic bond
Correct answer: Covalent bond
Covalent bonds form when two atoms share one or more pairs of electrons.
Question 3: What is the pH value of a neutral solution at room temperature?
- 0
- 5
- 7 (Correct answer)
- 14
Correct answer: 7
Pure water and neutral solutions have a pH of 7, where hydrogen and hydroxide ion concentrations are equal.
Question 4: Which state of matter has a definite volume but no definite shape?
- Solid
- Liquid (Correct answer)
- Gas
- Plasma
Correct answer: Liquid
Liquids have a fixed volume but take the shape of their container because their particles can flow past each other.
Question 5: Which element is the most abundant in Earth's atmosphere?
- Oxygen
- Carbon dioxide
- Nitrogen (Correct answer)
- Argon
Correct answer: Nitrogen
Nitrogen (N₂) makes up approximately 78% of Earth's atmosphere by volume.
Question 6: What is the process by which a solid changes directly into a gas without passing through the liquid phase?
- Evaporation
- Condensation
- Sublimation (Correct answer)
- Deposition
Correct answer: Sublimation
Sublimation occurs when a solid converts directly to a gas; dry ice (solid CO₂) is a common example.
Question 7: What is the chemical symbol for sodium?
- So
- Sd
- Na (Correct answer)
- Ni
Correct answer: Na
Sodium's symbol Na comes from the Latin word 'Natrium.'
Picat General Science 2
What is the atomic number of carbon?