1. Which contributes more to an atom’s mass electrons or protons? Which
contributes more to an atom’s size?
Protons contribute to an atom’s mass
Electrons contribute to an atom’s size
2. A hydrogen atom and a carbon atom move at the same speed. Which has the
greater kinetic energy?
3. Why do electrically neutral atoms repel one another when they are close?
The atoms that constitute your body are mostly empty space, and structures
such as the chair you’re sitting on are composed of atoms that are mostly
4. So why don’t you fall through the chair?
Electrons in one atom repel the electrons in another.
5. Avogrado’s number
Na= 6.0221415X10^23 mol-1
A mole will possess mass approximately equal to the substances molecular
6. A tree is composed mainly from carbon. Where does this carbon come from?
The air. Photosynthesis.
7. 1 column of the periodic table is alkaline and noble gases.
8. Isotopes: atoms of the same element that have different numbers of neutrons
9. Size of an atom does not change with mass.
10.An atom of antimatter has a negatively charged nucleus surrounded by
11.Atoms are smaller than
All of these
12.The size of atoms has most to do with its:
13.How many different elements are in a water molecule?
14.How many atoms are in a water molecule?
15.An atomic mass unit (amu) is 1/12 the mass of:
16.There are only about 100 different kinds of atoms that combine to form all
17.What makes an element distinct?
The number of protons.
18.In our part of the universe, antimatter is:
Short lived. 19.Solid matter is mostly empty space largely because:
Atom’s themselves are mostly empty space
20.What is the molecular mass of water?
21.In an electrically neutral atom, the number of protons in the nucleus is
balanced by an equal number of: