Q 01/05

What is hydrogen's atomic number?

A) 1

B) 2

C) 4

D) 8

Answer · why

A) 1

1: the number counts the positively charged particles in an atom's nucleus, and hydrogen has a single one, making it the lightest element and earning ...

Q 02/05

Hydrogen is about three-quarters of the universe's ordinary matter by mass; which element makes up almost all the rest?

A) Oxygen

B) Helium

C) Carbon

D) Iron

Answer · why

B) Helium

Helium is roughly a quarter of all ordinary matter. Every heavier element, from the oxygen you breathe to the iron in your blood, adds up to only abou...

Q 03/05

Under standard conditions, hydrogen gas is made of molecules with which formula?

A) H

B) H3

C) H2

D) H4

Answer · why

C) H2

H2: the bond between the two atoms is so strong that this famously flammable gas barely reacts at room temperature, until heat, a spark or a catalyst ...

Q 04/05

Which reclusive British scientist, who later 'weighed the Earth', identified hydrogen as a distinct substance in 1766?

A) Robert Boyle

B) Antoine Lavoisier

C) Joseph Priestley

D) Henry Cavendish

Answer · why

D) Henry Cavendish

Henry Cavendish collected the gas bubbling off metals in acid and showed it was unlike any other air; he suspected he had bottled phlogiston, the supp...

Q 05/05

What does the name 'hydrogen' mean?

A) Water-former

B) Acid-former

C) Light-bringer

D) Fire-air

Answer · why

A) Water-former

Water-former: the 1780s coinage joins the Greek for water to an ending meaning producing, because burning the gas makes water.