Atoms, organic compounds, trace elements

Everything in the universe that takes up space and has mass is called ___________________.

• atoms

• matter

• ions

• weight

The basic unit of matter is the ______________.

• cell

• stage

• atom

• proton

A substance that is made of only one kind of atom is a(n)__________________.

• element

• nucleus

• valence electron

• compound

The atomic number is the same as the number of _______________.

• neutrons

• protons

• neutrons + protons

• protons + electrons

Which element is present in ALL organic compounds?

• nitrogen

• calcium

• carbon

• zinc

How many valence electrons does Carbon have?

• 2

• 3

• 4

• 6

A chemical element whose concentration is very low in living tissues, but are essential for life are called ___________________.

• reactants

• trace elements

• enzymes

• catalysts

These bonds form when atoms are shared.

• covalent bonds

• ionic bonds

• hydrogen bonds

These bonds form between positively and negatively charged atoms.

• covalent bonds

• ionic bonds

• hydrogen bonds

Atoms that have an electrical charge are called ______________.

• protons

• electrons

• ions

• bonds