Q 01/05

What is carbon's atomic number?

A) 2

B) 6

C) 18

D) 54

Answer · why

B) 6

6. That leaves four electrons in its outer shell, which is why carbon usually forms four bonds.

Q 02/05

In diamond, each carbon atom's four bonds point to the corners of what shape?

A) Flat square

B) Tetrahedron

C) Cube

D) Octahedron

Answer · why

B) Tetrahedron

Tetrahedron. That rigid network of strong bonds is why diamond is the hardest natural substance.

Q 03/05

Coal formed mostly from the buried remains of what?

A) Ancient swamp plants

B) Marine plankton

C) Volcanic ash

D) Meteorite dust

Answer · why

A) Ancient swamp plants

Ancient swamp plants. They rotted into peat, and millions of years of heat and pressure under buried sediment turned that peat into coal.

Q 04/05

Carbon ranks where in abundance among elements in the universe by mass?

A) Second

B) Fourth

C) Tenth

D) Twentieth

Answer · why

B) Fourth

Fourth. Only hydrogen, helium and one heavier element outrank it, yet almost none of that carbon was made in the Big Bang.

Q 05/05

By mass, which element is more plentiful in the human body than carbon?

A) Calcium

B) Hydrogen

C) Nitrogen

D) Oxygen

Answer · why

D) Oxygen

Oxygen. Water makes up over half the body's weight, and water is mostly oxygen by mass.