Atomic theory

Question 1

What is an atom?

Answer 1

An atom is the smallest particle of an element, and the smallest unit of matter

Question 2

What is a molecule?

Answer 2

A molecule is two or more atoms whose bonds bind together making the smallest unit in a compound (Oxygen molecule = 2 atoms of oxygen)

Question 3

What is an element?

Answer 3

An element consists of one type of atom, each atom contains the same number of protons (Hydrogen)

Question 4

What is a compound?

Answer 4

A compound consists of 2 more elements that are chemically bonded (held together by covalent or ionic bonds) in a fixed ratio, e.g. a water molecule (H2O), magnesium oxide (MgO)

Question 5

What is a mixture?

Answer 5

A mixture is the physical combination of 2 or more substances in which the identities of the individual substances are retained, e.g., salt water (NaCl + H2O)

Question 6

What is matter?

Answer 6

Matter is anything that has mass and volume

Question 7

.

Answer 7

The

- Electrons travel around the nucleus in circular orbits

Question 8

Structure of atom: Electron

Answer 8

Location: Electron cloud
Charge: -1
Relative mass: 1/1800

Question 9

Structure of atom: Proton

Answer 9

Location: Nucleus
Charge: +1
Relative mass: 1

Question 10

Structure of atom: Neutron

Answer 10

Location: Nucleus
Charge: 0
Relative mass: 1

Question 11

What does an electron cloud do?

Answer 11

The negatively charged electron cloud gives atoms their size and mass

Question 12

Describe the nucleus

Answer 12

The nucleus is 10,000-100,000 times smaller than the size of an atom but contributes to 99.97% of the mass - nuclei are very dense

Question 13

What keeps atoms bound together?

Answer 13

Electrostatic attraction b/w electrons and protons keep the atom bound together

Question 14

What is the atomic number?

Answer 14

The atomic number is the number of protons in the nucleus and is at the bottom of the chemical symbol

Question 15

What is the mass number?

Answer 15

The mass number is the total number of protons and neutrons in nucleus, written at the top of the chemical symbol

Question 16

How can you find the number of electrons?

Answer 16

The number of protons = number of electrons

Question 17

How can you find the number of neutrons w the atomic number?

Answer 17

The atomic mass = the number of protons + neutrons, so take away the atomic mass from the atomic number which will give you the number of neutrons

Question 18

What is electron configuration?

Answer 18

Shows the arrangement of electrons in an atom, where the number of electrons in each is separated by a comma

Question 19

What is an ion?

Answer 19

A charged particle. Occurs as electrons may be gained or lost from the valence shell, when the number of protons and electrons are no longer equal, it produces a charged particle

Question 20

What are anions?

Answer 20

Negatively charged ions, as electron is gained and outnumbers the number of protons

Question 21

What are cations?

Answer 21

Positively charged, as electron is lost and protons outnumber electrons

Question 22

Why do atoms lose/gain electrons?

Answer 22

Atoms tend to lose/gain electrons to achieve a full valence shell, giving it a similar configuration to the nearest noble gas

Question 23

Which type of atoms become cations?

Answer 23

Metals tend to lose electrons, such as Mg

Question 24

Which type of atoms become anions?

Answer 24

Non-metals tend to gain electrons such as Cl

Question 25

How are the names of anions changed?

Answer 25

Anions are changed to end in -ide, for example chlorine turns to chloride, and oxygen turns to oxide

Question 26

What is relative molecular mass?

Answer 26

(Mr) is the mass of a molecule of a substance relative to the mass of a carbon-12 atom. It is equal to the sum of the relative atomic masses of the atoms in the molecule

Question 27

How can you calculate the relative molecular mass?

Answer 27

1) identify elements that make up the element
2) identify the no. of atoms that make up the element
3) add the relative mass of atoms that make up the element