Q 01/05

The word 'atom' comes from the ancient Greek 'atomos', which described matter as being what?

A) Eternal

B) Uncuttable

C) Weightless

D) Invisible

Answer · why

B) Uncuttable

Uncuttable is what 'atomos' meant, an idea so old that it appeared in several ancient cultures long before anyone could test it.

Q 02/05

By roughly what factor does a proton outweigh an electron, leaving the nucleus with nearly all an atom's mass?

A) 9,180

B) 18,360

C) 1,836

D) 3,672

Answer · why

C) 1,836

1,836 to one is the proton-to-electron mass ratio, yet the two particles carry exactly equal and opposite charges.

Q 03/05

Which radioactive isotope with a 12-year half-life makes exit signs and watch hands glow with no power source?

A) Radium-226

B) Carbon-14

C) Cobalt-60

D) Tritium

Answer · why

D) Tritium

Tritium is hydrogen with two neutrons, its name from the Greek 'tritos', meaning 'third'; its half-life is 12.32 years.

Q 04/05

A neutron pulled out of a nucleus is unstable; what is a free neutron's mean lifetime before decaying into a proton?

A) About 15 hours

B) About 15 years

C) About 15 minutes

D) About 15 seconds

Answer · why

C) About 15 minutes

About 15 minutes on average, leaving a proton, an electron and an antineutrino; the neutron is itself slightly heavier than the proton it becomes.

Q 05/05

The name for the atom's dense centre, adopted by Rutherford in 1912, is a Latin diminutive of the word for what?

A) Fig

B) Nut

C) Peach

D) Grape

Answer · why

B) Nut

Nut is nux in Latin, and 'nucleus' is its diminutive, the 'little nut' inside a fleshy fruit; Rutherford borrowed the word for the atom's core.