PAX PAX Chemistry and Physical Science 1 — Questions and Answers
Question 1: What is the atomic number of an element?
- The number of neutrons in the nucleus
- The number of protons in the nucleus (Correct answer)
- The total mass of the atom
- The number of electrons in the outer shell
Correct answer: The number of protons in the nucleus
The atomic number equals the number of protons in an atom's nucleus and identifies the element.
Question 2: What type of bond is formed when electrons are shared between atoms?
- Ionic bond
- Metallic bond
- Covalent bond (Correct answer)
- Hydrogen bond
Correct answer: Covalent bond
A covalent bond forms when two atoms share electrons to achieve a stable configuration.
Question 3: What is the pH of a neutral solution?
- 0
- 5
- 7 (Correct answer)
- 14
Correct answer: 7
A neutral solution, such as pure water, has a pH of 7; below 7 is acidic and above 7 is basic.
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 definite volume but take the shape of their container because their molecules can flow.
Question 5: What is the chemical formula for water?
- HO
- H₂O₂
- H₂O (Correct answer)
- OH₂
Correct answer: H₂O
Water is composed of two hydrogen atoms bonded to one oxygen atom, giving it the formula H₂O.
Question 6: Which subatomic particle has a negative charge?
- Proton
- Neutron
- Electron (Correct answer)
- Nucleus
Correct answer: Electron
Electrons carry a negative charge and orbit the nucleus of an atom.
PAX PAX Chemistry and Physical Science 1
What is the atomic number of an element?