Atoms
What is the charge of a proton?
Positive (+1)
What types of elements form ionic bonds?
Metals + non-metals
Name NaCl.
Sodium chloride (table salt)
Why is conductivity important for electricians?
Metals conduct electricity, used in wiring.
Which particle moves around the nucleus in shells?
Electrons
What types of elements form covalent bonds?
Non-metals + non-metals
Name CO₂.
Carbon dioxide
Why does vinegar make a good cleaner?
Its acidity dissolves mineral deposits and kills bacteria.
Oxygen has 8 protons. How many electrons does it have in a neutral atom?
8
In NaCl, which atom gives away an electron?
Sodium (Na)
Which dissolves in water: salt or oil?
Salt
Why is salt used on icy roads in winter?
It lowers the freezing point of water (melts ice).
What is the difference between mass number and atomic number?
Atomic number = protons; Mass number = protons + neutrons
Do ionic or covalent compounds have higher melting points?
Ionic compounds
Which of these is covalent: Na₂O, CaCl₂, CO?
CO (carbon monoxide)
Why is high melting point important for building materials like steel?
They don’t melt or weaken easily when exposed to heat.
If carbon has 6 protons and 7 neutrons, what is its mass number?
13
True or False – Covalent compounds conduct electricity in water.
False
What kind of compound is wax – ionic or covalent?
Covalent
Why must medicines dissolve in the body?
So they can be absorbed into the bloodstream and be effective.