Chemistry Grade 10: Semester 1

Question 1

What is the number of protons in an atom?

Answer 1

number of protons = atomic number

Question 2

What is the number of electrons in a neutral atom?

Answer 2

number of electron = proton number

Question 3

What is the mass number of an atom?

Answer 3

mass number = proton number + neutron number

Question 4

What is a cation?

Answer 4

positively charged ions (lose electron)

Question 5

What is an anion?

Answer 5

negatively charged ions (gain electron)

Question 6

What are the properties of Group 1 or Group IA (alkali metals)?

Answer 6

Group 1 elements are soft, highly reactive, and have low melting points. They form +1 cations.

Question 7

What are the properties of Group 17 or Group VIIA (halogens)?

Answer 7

Group 17 elements are highly reactive nonmetals and form -1 anions.

Question 8

What is electron configuration?

Answer 8

Electron configuration is the arrangement of electrons in the orbitals of an atom.

Question 9

What is relative atomic mass?

Answer 9

Relative atomic mass is the weighted average mass of an element’s isotopes, compared to 1/12 the mass of a carbon-12 atom.

Question 10

The subshells of an atom are …

Answer 10

s (1 orbital) = 2 electrons
p (3 orbitals) = 6 electrons
d (5 orbitals) = 10 electrons
f (7 orbitals) = 14 electrons

Question 11

What is a neutral atom?

Answer 11

A neutral atom has an equal number of protons and electrons, so it has no overall charge.

Question 12

What is an ion?

Answer 12

An ion is an atom or molecule with a net electric charge due to the loss or gain of electrons.

Question 13

What did Dalton’s Atomic Theory propose?

Answer 13

Dalton’s theory proposed that all matter is composed of atoms, which are indivisible and indestructible.

Question 14

What did Rutherford’s gold foil experiment discover?

Answer 14

Rutherford’s experiment discovered the nucleus, a dense positively charged center in an atom. He also discovered that there’s a vacuum between the electron and nucleus (didn’t discover orbit)

Question 15

What term did Democritus introduce?

Answer 15

Democritus introduced the term “atom” from the word atomos (can’t be divided)

Question 16

How did J.J. Thompsoon describe an atom?

Answer 16

He described an atom as a solid (non-hollow) ball with a positive charge and negatively charged electrons scattered around. (doesn’t show orbit)

Question 17

How does Niels Bohr explain the properties of an atom?

Answer 17

Bohr stated that electrons surround the nucleus through a stationary trajectory called the orbit. The nucleus of an atooom is positively charged. Electrons can move from one atom’s shell to another atom’s shell by emitting and absorbing energy.

Question 18

What is an element?

Answer 18

An element is a substance consisting of one type of atom.

Question 19

What is a compound?

Answer 19

A compound is a substance formed from two or more different elements chemically bonded.

Question 20

What is a mixture?

Answer 20

A mixture is a combination of two or more substances that are not chemically bonded.

Question 21

How is electron configuration related to the periodic table?

Answer 21

Electron configuration helps determine an element’s position in the periodic table, such as its group and period.

Question 22

What does the group number tell you?

Answer 22

The group number indicates the number of valence electrons in an element.

Question 23

What is are isotopes, isotones, are isobars?

Answer 23

isotopes = elements with the same number of proton
isotone = elements with the same number of neutrons
isobars = elements with the same mass.

Question 24

What are the three primary states of matter on Earth?

Answer 24

solid, liquid, and gas.

Question 25

What is a characteristic of solids?

Answer 25

Solids have a fixed shape and volume, with particles arranged in a structured, tight pattern

Question 26

What is a characteristic of liquids?

Answer 26

Liquids have a definite volume but no fixed shape, and particles can move past one another.

Question 27

What is a characteristic of gases?

Answer 27

Gases have no fixed shape or volume, and particles are far apart and move freely.

Question 28

What is the difference between solids, liquids, and gases?

Answer 28

Solids have fixed shape and volume, liquids have a fixed volume but no fixed shape, and gases have neither fixed shape nor volume.

Question 29

What are the transitions between the states of matter? (there are 6)

Answer 29

1. Melting = solid to liiquid 2. Freezing = liquid to solid 3. Evaporation = liquid to gas 4. Condensation = gas to liquid 5. Sublimation = solid to gas 6. Deposition = gas to solid

Question 30

What is chemistry?

Answer 30

Chemistry is the study of matter, its properties, reactions, and the changes it undergoes.

Question 31

What are the two main classifications of matter?

Answer 31

Matter can be classified as either a substance (elements or compounds) or a mixture (homogeneous or heterogeneous).

Question 32

What was Thomson’s atomic model?

Answer 32

"plum pudding" model

Question 33

What is a homogeneous mixture?

Answer 33

A homogeneous mixture has uniform composition throughout, like a solution.

Question 34

What is a heterogeneous mixture?

Answer 34

heterogeneous mixture has a non-uniform composition, like a salad.

Question 35

What is a beaker used for?

Answer 35

A beaker is used for holding and heating liquids in a laboratory. (prepare mixture, not measure)

Question 36

What is a Bunsen burner used for?

Answer 36

A Bunsen burner is used for heating substances with an open flame.

Question 37

What does the "flammable" hazard sign indicate?

Answer 37

indicates that the substance can easily catch fire.

Question 38

What is green chemistry?

Answer 38

Green chemistry is the design of chemical products and processes that reduce or eliminate the use of hazardous substances.

Question 39

What is nanotechnology?

Answer 39

Nanotechnology is the manipulation of matter on an atomic or molecular scale, often involving materials smaller than 100 nanometers.

Question 40

What are nanomaterials?

Answer 40

Nanomaterials are materials with structures at the nanoscale that exhibit unique physical and chemical properties.

Question 41

Why is surface area important in nanotechnology?

Answer 41

Nanoparticles have a high surface area to volume ratio, which makes them more reactive and useful in various applications.

Question 42

What are some health risks of nanotechnology?

Answer 42

Nanoparticles can be toxic if inhaled or ingested, as they can penetrate cells and tissues.

Question 43

List the following particles from the smallest to the largest: Hydrogen ion, molecule of carbon dioxide, atom of oxygen, water molecule, nanoparticle, bacterium, virus

Answer 43

hydrogen ion, atom of oxygen, water molecule, molecule of carbon dioxide, nanoparticle, virus, bacterium.