Measurement & Changes
What unit is used to measure liquid volume in science?
Liter (L)
Which subatomic particle has a positive charge?
Proton
What is the atomic number of iodine (I)?
53
How many valence electrons do elements in Group 14 have?
4
Which law says an object at rest stays at rest unless acted on by a force?
Newton’s First Law (Law of Inertia)
What unit do scientists use to measure mass?
Gram (g)
Which subatomic particle has no charge?
Neutron
What is the symbol for silver?
Ag
Which type of bond involves the transfer of electrons?
Ionic bond
Which law explains that force causes acceleration?
Newton’s Second Law
Is melting ice a physical or chemical change?
Physical change
Which particle moves around the nucleus?
Electron
Is oxygen a metal or non-metal?
Non-metal
In water (H₂O), are electrons shared or transferred?
Shared (covalent bond)
A 10 N force pushes a 2 kg box. What is the acceleration?
5 m/s² (acceleration = force ÷ mass → 10 ÷ 2 = 5)
Cutting an apple: physical or chemical? Explain.
Physical change – cutting changes shape but not composition.
An atom has 6 protons. What element is it?
Carbon (C)
Find the element in Group 15, Period 3. Name it.
Phosphorus (P)
Explain why lithium and chlorine form an ionic bond.
Lithium loses 1 electron and chlorine gains 1 electron; the opposite charges attract, forming an ionic bond
A 5 kg object accelerates at 4 m/s². What is the force?
20 N (force = mass × acceleration → 5 × 4 = 20)
Explain one difference between a physical change and a chemical change.
Physical changes do not change the substance’s identity; chemical changes form new substances with new properties. Physical changes can be reversed Chemical changes can not.
Why does the atomic number identify an element?
The atomic number equals the number of protons, which is unique for each element
Name one alkali metal and give one property that makes it reactive.
Lithium (Li) – highly reactive because it has 1 valence electron that it easily loses
Why are valence electrons important in chemical bonding?
Valence electrons determine how atoms bond; they are responsible for forming chemical bonds
Explain the Law of Conservation of Momentum in your own words.
The total momentum of a system stays the same unless acted on by an outside force