OTEE General Science Principles 3 — Questions and Answers
Question 1: On the periodic table, elements in the same vertical column (group) share which characteristic?
- The same number of protons
- The same number of neutrons
- The same number of valence electrons (Correct answer)
- The same atomic mass
Correct answer: The same number of valence electrons
Elements in the same group have the same number of valence electrons, giving them similar chemical properties.
Question 2: In an ionic bond, what happens to electrons?
- They are shared equally between atoms
- They are shared unequally between atoms
- One atom transfers electrons to another (Correct answer)
- Electrons orbit both nuclei simultaneously
Correct answer: One atom transfers electrons to another
In ionic bonding, one atom donates electrons to another, creating oppositely charged ions that attract each other.
Question 3: A solution with a pH of 3 is best described as:
- Strongly basic
- Weakly basic
- Weakly acidic
- Strongly acidic (Correct answer)
Correct answer: Strongly acidic
pH values below 7 indicate acidic solutions; pH 3 is strongly acidic because each unit below 7 represents a tenfold increase in acidity.
Question 4: In a chemical reaction, the Law of Conservation of Mass requires that:
- Products always weigh more than reactants
- The number of molecules is equal on both sides
- Total mass of reactants equals total mass of products (Correct answer)
- Energy is released in every reaction
Correct answer: Total mass of reactants equals total mass of products
The Law of Conservation of Mass states that matter is neither created nor destroyed, so reactant mass equals product mass.
Question 5: 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 one another.
Question 6: Which subatomic particle determines the atomic number of an element?
- Neutron
- Electron
- Proton (Correct answer)
- Positron
Correct answer: Proton
The atomic number equals the number of protons in the nucleus, which uniquely identifies each element.
Question 7: Adding a solute to a pure solvent will:
- Raise its boiling point and raise its freezing point
- Lower its boiling point and lower its freezing point
- Raise its boiling point and lower its freezing point (Correct answer)
- Have no effect on its boiling or freezing point
Correct answer: Raise its boiling point and lower its freezing point
Dissolved solutes cause boiling point elevation and freezing point depression, both colligative properties of solutions.
OTEE General Science Principles 3
On the periodic table, elements in the same vertical column (group) share which characteristic?