Particle Theory
Which state of matter has particles closest together?
Solid
Burning wood is what type of change?
Chemical change
What does atomic number represent?
Number of protons
What happens to particles when a substance is heated?
They move faster
Kimchi is made through fermentation.
Is fermentation a physical or chemical change?
Chemical change
Where are protons found in an atom?
Nucleus
Why can gases be compressed?
The particles are far apart
Gas, temperature change, colour change, new substance
How do you find the number of neutrons?
Mass number – atomic number
Describe particle movement in a liquid.
Close together, but can move past each other
A candle is lit. What two types of change are happening?
Physical (melting wax) + Chemical (burning)
A neutral atom has an atomic number of 12, and a mass of 24.
How many protons, neutrons, and electrons does it have?
12 protons
12 electrons (neutral)
12 neutrons (24 – 12)
Explain what happens to particles during a chemical reaction.
Atom rearrange to form new substances
Ethanol is first frozen and then burned.
What types of changes are occurring? Explain your answer.
Freezing ethanol → Physical
It is only changing state (liquid to solid), no new substance is formed.
Burning ethanol → Chemical
It reacts with oxygen to form new substances (CO2 and H2O) and releases energy (heat).
An atom has 17 protons and 18 electrons.
Is this atom neutral or an ion? Explain your answer.
Ion, negative charge (-1), because it has more electrons than protons.