Structure of an Atom

The Greek philosopher Democritus called the minute particles that made up matter 'atoms', which means ________.

• inflammable

• invincible

• indivisible

• inevitable

In the year _______, an English scientist _____________ described an atom as the smallest particle which exhibits all the properties of an element.

• 1809; John Dalton

• 1908; JJ Thompson

• 1808; John Dalton

• None of the above

An atom is electrically neutral but can be made to gain a positive or negative charge.

• True

• False

Electrons were discovered in 1878 by _____________.

Which British scientist studied William Crookes's experiment with cathode rays?

• JR Thompson

• JJ Thompson

• Democritus

• None of the above

An electron is denoted by _-1e⁰ where the 0 represents the ________ and the -1 represents the ________.

• electrical charge; mass

• mass; electrical charge

• None of the above

The mass of an electron is __________.

• 9­·108*10^-28g

• 1·602*10^-19g

The mass of a proton is __________.

• 1·672*10^-24g

• 1·602*10^-19g

What was JJ Thompson's model of an atom called?

• The plum pudding model

• The plum cake model

• The dry fruit pudding model

• None of the above

In an atom, what is the number of protons equal to?

• The number of electrons.
• The number of neutrons.
• The number of molecules.
• The number of nuclei.

Tags

NGSS.MS-PS1-1