Module 3 - Atoms, Molecules, and Ions

Question 1

Who formed a theory about atoms?

Answer 1

John Dalton

Question 2

What are the main postulates of Dalton’s atomic theory?

Answer 2

1. All matter is composed of tiny, indivisible particles called atoms.
2. All atoms of a specific element are identical in mass, size, and other properties. (However, atoms of different elements exhibit different properties and vary in mass and size.)
3. Atoms can neither be created nor destroyed. Furthermore, atoms cannot be divided into smaller particles.
4. Atoms of different elements can combine in fixed whole-number ratios to form compounds.
5. Atoms can be rearranged, combined, or separated in chemical reactions.

Question 3

What was the reason why Dalton’s atomic theory had to be modified?

Answer 3

The discovery of subatomic particles and isotopes.

Question 4

Law of matter that refers to the total mass of substances present after a chemical reaction is the same as the total mass of substances before the reaction.

Answer 4

Law of conservation of mass

Question 5

Law of matter that refers to all samples of a compound have the same composition—the same proportions by mass of the constituent elements.

Answer 5

Law of constant composition

Question 6

It is the fundamental building
block of all matter and chemistry.

Answer 6

Atoms

Question 7

A subatomic particle that is a small negatively charged particles that orbit around an atom’s positively charged nucleus.

Answer 7

Electrons

Question 8

A subatomic particle that is a smaller bit of positively charged matter or sub-atomic particle within the nucleus.

Answer 8

Protons

Question 9

The mass of a proton is _____ times greater than an electron

Answer 9

1800

Question 10

A subatomic particle that refers to the particles located inside the nucleus with a similar mass to their partner proton but with no electrical charge.

Answer 10

Neutrons

Question 11

Defined as the total number of protons and neutrons in an atom.

Answer 11

Mass number

Question 12

_______ are composed of atoms chemically bonded by attractive forces.

Answer 12

Molecules

Question 13

These are the elements that occur naturally in pairs or as two-atoms.

Answer 13

Diatomic molecules

Question 14

Refers to the force that binds two or more atoms together.

Answer 14

Chemical bond

Question 15

A bond wherein electrons are shared equally.

Answer 15

Covalent bond

Question 16

A bond when electrons are transferred from one atom to another.

Answer 16

Ionic bond

Question 17

A bond that is formed between two non-metals that have similar electronegativities.

Answer 17

Covalent bond

Question 18

A bond that is formed between a metal and a non-metal.

Answer 18

Ionic bond

Question 19

A formula that gives the exact number of atoms of each element in a molecule.

Answer 19

Molecular formula

Question 20

A formula that shows how specific atoms are ordered and arranged in compounds. It makes it easier to see how atoms are bonded.

Answer 20

Structural formula

Question 21

These are the atoms that lose or gain electrons. Atoms are electrically neutral or uncharged.

Answer 21

Ions

Question 22

Positively charged ion

Answer 22

Cation

Question 23

Negatively charged ion

Answer 23

Anion