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Question 1

Define an isotope.

Answer 1

Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons.

Question 2

What is the formula to calculate the number of neutrons in an atom?

Answer 2

Number of neutrons = Mass number - Atomic number

Question 3

State the three subatomic particles and their charges.

Answer 3

Answer: Proton (+1 charge), Neutron (0 charge), Electron (-1 charge)

Question 4

What is the mass number of an atom?

Answer 4

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

Question 5

Define the term ‘compound’.

Answer 5

A substance formed by the chemical combination of two or more elements in fixed proportions.

Question 6

What is the difference between an element and a compound?

Answer 6

An element is a substance made of only one type of atom, while a compound is made of two or more different types of atoms chemically combined.

Question 7

State the Law of Conservation of Mass.

Answer 7

The total mass of substances involved in a chemical reaction remains constant before and after the reaction.

Question 8

Define a mixture.

Answer 8

A mixture is a substance made by mixing other substances together without a chemical reaction occurring.

Question 9

What is a physical change? Give an example.

Answer 9

A physical change is a change in which no new substance is formed. Example: Melting ice into water.

Question 10

State the properties of metals.

Answer 10

Metals are shiny, malleable, ductile, and good conductors of heat and electricity.

Question 11

What is the reactivity series?

Answer 11

A list of metals arranged in order of their reactivity, with the most reactive metal at the top and the least reactive at the bottom.

Question 12

Define oxidation.

Answer 12

The gain of oxygen or loss of electrons by a substance.

Question 13

What is a displacement reaction?

Answer 13

A reaction in which a more reactive element displaces a less reactive element from its compound.

Question 14

State the products of the reaction between an acid and a metal

Answer 14

Salt and hydrogen gas.

Question 15

What are the properties of alkali metals?

Answer 15

Alkali metals are soft, shiny, and highly reactive. They have low melting and boiling points.

Question 16

How do alkali metals react with water?

Answer 16

Alkali metals react vigorously with water to form an alkaline solution and hydrogen gas.

Question 17

Name three elements in Group 1.

Answer 17

Lithium, Sodium, Potassium

Question 18

What happens to the reactivity of alkali metals as you move down the group?

Answer 18

The reactivity of alkali metals increases as you move down the group

Question 19

What are the properties of halogens, group 7?

Answer 19

Halogens are nonmetals, highly reactive, and exist in various physical states at room temperature.

Question 20

Name three elements in Group 7.

Answer 20

Fluorine, Chlorine, Bromine

Question 21

How does the reactivity of halogens change as you move down the group?

Answer 21

The reactivity of halogens decreases as you move down the group.

Question 22

What happens when halogens react with metals?

Answer 22

Halogens react with metals to form metal halides.

Question 23

What are the characteristics of transition metals?

Answer 23

Transition metals have high melting and boiling points, form colored compounds, and often act as catalysts.

Question 24

Why are transition metals good conductors of electricity?

Answer 24

Transition metals have delocalized electrons that can move freely, allowing them to conduct electricity.

Question 25

What was the basis for Mendeleev's arrangement of elements in the periodic table?

Answer 25

Mendeleev arranged elements based on their increasing atomic mass and similar chemical properties.

Question 26

What was the major flaw in Mendeleev's periodic table?

Answer 26

There were gaps in Mendeleev's periodic table for undiscovered elements.

Question 27

What are some key features of the modern periodic table?

Answer 27

The modern periodic table is arranged based on increasing atomic number and organized into periods and groups based on similar chemical properties.

Question 28

What happens when alkali metals react with oxygen?

Answer 28

Alkali metals react with oxygen to form metal oxides.

Question 29

How do alkali metals react with chlorine?

Answer 29

Alkali metals react with chlorine to form metal chlorides.

Question 30

What are the physical states of alkali metals at room temperature?

Answer 30

Alkali metals are solids at room temperature.

Question 31

How does the reactivity of alkali metals compare to other metals in the periodic table?

Answer 31

Alkali metals are more reactive than other metals in the periodic table.

Question 32

Describe the trend in melting points of halogens as you move down the group.

Answer 32

The melting points of halogens increase as you move down the group.

Question 33

What happens when halogens react with non-metals?

Answer 33

Halogens react with non-metals to form covalent compounds.

Question 34

What are the physical states of halogens at room temperature?

Answer 34

Fluorine and chlorine are gases, bromine is a liquid, and iodine is a solid at room temperature.

Question 35

How does the color of halogens change as you move down the group?

Answer 35

The color of halogens becomes darker as you move down the group, from pale yellow (fluorine) to dark purple (iodine).

Question 36

How do the melting and boiling points of transition metals compare to alkali metals?

Answer 36

The melting and boiling points of transition metals are generally higher than those of alkali metals.

Question 37

How did the discovery of isotopes contribute to the development of the periodic table?

Answer 37

The discovery of isotopes helped explain anomalies in the periodic table and refine the concept of atomic mass.