Atoms and Molecules
Science · Grade 9 · Week 4 · 25 questions
Atoms are the tiny particles that make up everything in the universe. Understanding atomic structure, elements, and compounds is the foundation of chemistry.
What you'll practise
- Describe the structure of an atom
- Distinguish between elements and compounds
- Understand atomic number and mass number
- Explain how atoms combine to form molecules
All 25 questions in this Atoms and Molecules quiz
Grade 9 Science — Atoms and Molecules: 25 practice questions with instant scoring and explanations.
- According to Dalton's atomic theory, all matter is made of:
- The atomic mass of an element is primarily due to:
- One mole of any substance contains:
- The molecular mass of CO₂ is: (C = 12, O = 16)
- Valency is defined as:
- The chemical formula of magnesium oxide is:
- An atom of chlorine has atomic number 17. Its valency in chlorides is:
- How many atoms are present in one molecule of H₂SO₄?
- The relative atomic mass of carbon is 12. How many moles are in 24 g of carbon?
- Which pair of atoms has the same number of electrons in a neutral state?
- The empirical formula is:
- What is the molar mass of H₂O? (H = 1, O = 16)
- An element has atomic mass 35.5. The most likely element is:
- The formula of calcium carbonate is:
- How many moles of oxygen atoms are in 2 moles of CaCO₃?
- The valency of aluminum in Al₂O₃ is:
- Avogadro's number is:
- What is the percentage composition of hydrogen in H₂O? (H = 1, O = 16)
- The molecular formula of a compound can be determined from its empirical formula if we know:
- The number of molecules in 0.5 mol of O₂ is:
- An atom with atomic number 19 has how many valence electrons?
- The empirical formula and molecular formula are the same for:
- What is the mass of 1 mole of NaCl? (Na = 23, Cl = 35.5)
- Dalton's atomic theory states that atoms of the same element:
- The valency of nitrogen in NH₃ is:
Question 1 of 250 correct so far