Particles

Question 1

What is a pure substance?

Answer 1

A material made up of only one type of particle.

This includes elements and compounds.

Question 2

How is each element represented?

Answer 2

By a unique symbol.

Question 3

What does the atomic number of an element represent?

Answer 3

The number of protons in the element.

Question 4

Where are all known elements listed?

Answer 4

On the periodic table of elements.

Question 5

What do elements in the same group have in common?

Answer 5

They have the same number of valence electrons.

Question 6

What do elements in the same period have in common?

Answer 6

They have the same number of energy levels.

Question 7

What are the main categories of elements?

Answer 7

• Metals
• Non-metals
• Metalloids

Question 8

What are characteristics of metals?

Answer 8

• Good conductors of heat and electricity
• Sonorous
• Shiny (lustrous)
• Malleable
• Ductile
• Found on the left-hand side of the periodic table

Question 9

What are characteristics of non-metals?

Answer 9

• Poor conductors of heat and electricity
• Dull
• Brittle
• Found on the right-hand side of the periodic table

Question 10

What are metalloids?

Answer 10

Elements that have both metal and non-metal properties.

Question 11

Where are metalloids located on the periodic table?

Answer 11

Around the zigzag line separating metals and non-metals.

Question 12

What are examples of diatomic molecules?

Answer 12

• H2
• O2
• N2
• Cl2
• Br2
• I2
• F2

Question 13

What is the ratio of atoms in a compound?

Answer 13

Atoms are always in a fixed ratio.

Question 14

How are compounds formed?

Answer 14

Through chemical reactions.

Question 15

How can compounds be broken down?

Answer 15

By chemical methods like heating or electrolysis (decomposition).

Question 16

What are covalent (molecular) compounds?

Answer 16

Compounds made of non-metal atoms sharing electrons.

Question 17

What are ionic compounds?

Answer 17

Usually made of metals and non-metals, formed when atoms transfer electrons.

Question 18

What do ionic compounds create?

Answer 18

Positive and negative ions that attract each other.

Question 19

What do organic compounds contain?

Answer 19

Carbon and are found in living things.

Question 20

What is a separating method?

Answer 20

A way to split a mixture into its different parts based on behavior such as size, solubility, boiling point, or magnetic properties.

Question 21

What is filtration?

Answer 21

Separates insoluble solids from liquids using a filter.

Question 22

What is evaporation?

Answer 22

Removes a liquid by heating, leaving the dissolved solid behind.

Question 23

What is fractional distillation?

Answer 23

A process used to separate a mixture of liquids with different boiling points.

Question 24

What is distillation?

Answer 24

A process used to separate a liquid from a solution based on boiling points.

Question 25

What is centrifugation?

Answer 25

Spins mixtures to separate substances by density.

Question 26

What is chromatography?

Answer 26

Separates substances based on how they move through a medium.

Question 27

What does magnetism do in separating methods?

Answer 27

Uses a magnet to separate magnetic materials from non-magnetic ones.

Question 28

What is sieving?

Answer 28

Uses a sieve to separate particles of different sizes.

Question 29

What is decanting?

Answer 29

Separates liquids from solids by pouring off the liquid.

Question 30

What characterizes a homogeneous mixture?

Answer 30

Particles are evenly mixed and look the same throughout.

Question 31

What is a solution?

Answer 31

A homogeneous mixture where one substance (solute) dissolves completely in another (solvent).

Question 32

What characterizes a heterogeneous mixture?

Answer 32

Particles are not evenly mixed; different parts are visible.

Question 33

What is a suspension?

Answer 33

A heterogeneous mixture with large particles that float at first but eventually settle.

Question 34

Fill in the blank: A solution has one substance (solute) that dissolves completely in another (________).

Answer 34

[solvent]

Question 35

True or False: In a homogeneous mixture, different parts are visible.

Answer 35

False

Question 36

True or False: Centrifugation can be used to separate cream from milk.

Answer 36

True