week 1, concept 3 : Terminology

Question 1

etymology-

the word atom comes from _ and means _

Answer 1

• Greek word atomos
• ‘indivisible’ based on ‘not to cut’

Question 2

Compounds are formed by the chemical combination of… different kinds of atoms.

Answer 2

two or more

Question 3

A molecule is a _ combination of two or more atoms that acts as a_.

Answer 3

_tightly bound

_single unit

Question 4

Monatomic elements

Answer 4

consist of single atoms;

for example, helium (He) and neon (Ne).

Question 5

Diatomic elements:

Answer 5

There are seven elements that occur as diatomic molecules:

Question 6

Polyatomic elements:

Answer 6

Some elements have three or more atoms per molecule:

(Diamond has millions of carbon atoms bonded together to form one gigantic cluster.)

Question 7

atomic mass unit

Answer 7

The unit of mass

(amu)

Question 8

Mass number:

Answer 8

The sum of the number of protons and neutrons in the nucleus of an atom.

Question 9

Atomic number:

Answer 9

The number of protons in the nucleus of an atom.

Question 10

Isotopes:

Answer 10

Atoms with the same number of protons but a different number of neutrons.

Carbon-12 has 6 protons and 6 neutrons
Carbon-13 has 6 protons and 7 neutrons
Carbon-14 has 6 protons and 8 neutrons

Most elements found on Earth are mixtures of isotopes.
Chlorine is 75.77% chlorine-35 (18 neutrons) and 24.23% chlorine-37 (20 neutrons).

Question 11

Atomic weight:

Answer 11

The weighted average of the masses (in amu) of the naturally occurring isotopes of an element.

Example: Chlorine is 75.77% chlorine-35 and 24.23% chlorine-37