Quiz about Chemistry in Living Systems: Unit 2 Worksheet

Question 1

Why is water considered crucial for life on Earth?

Accepted Answer

Because it supports all known forms of life

Answer

Because it is the only liquid on Earth

Answer

Because it is always found in solid form

Answer

Because it is not needed by organisms

Question 2

Which property of water makes it important to organisms?

Accepted Answer

Its ability to dissolve many substances

Answer

Its solid state at room temperature

Answer

Its lack of interaction with other chemicals

Answer

Its inability to change temperature

Question 3

How is matter changed in chemical reactions?

Accepted Answer

Matter is rearranged to form new substances

Answer

Matter disappears completely

Answer

Matter remains exactly the same

Answer

Matter turns into energy only

Question 4

How do organisms use chemistry to survive?

Accepted Answer

By using chemical reactions to obtain energy and build materials

Answer

By ignoring chemical reactions

Answer

By avoiding all chemical changes

Answer

By only using physical changes

Question 5

What materials are organisms made of?

Accepted Answer

A variety of chemical compounds

Answer

Only water

Answer

Only metals

Answer

Only gases

Question 6

What role do chemical reactions play when food encounters gastric juice in your stomach?

Accepted Answer

They help break down the food.

Answer

They make the food taste better.

Answer

They cool down the food.

Answer

They change the color of the food only.

Question 7

Which of the following best describes what happens to food when it undergoes a chemical reaction in the stomach?

Accepted Answer

The food is broken down into simpler substances.

Answer

The food is physically mixed but not changed.

Answer

The food is frozen.

Answer

The food is turned into gas only.

Question 8

Why is it important for food to undergo chemical reactions in the stomach?

Accepted Answer

To make it easier for the body to absorb nutrients.

Answer

To make the food look more appealing.

Answer

To keep the food whole for longer.

Answer

To increase the temperature of the food.

Question 9

What is the smallest basic unit of matter?

Accepted Answer

Atom

Answer

Molecule

Answer

Element

Answer

Compound

Question 10

Which of the following best describes an element?

Accepted Answer

A substance made of one type of atom that cannot be broken down into simpler substances by chemical reactions

Answer

A mixture of different atoms

Answer

A combination of molecules

Answer

A substance that can be separated into simpler substances by physical means

Question 11

Why can't an element be broken down into simpler substances by chemical reactions?

Accepted Answer

Because it is made of only one type of atom

Answer

Because it is made of many types of atoms

Answer

Because it is a mixture

Answer

Because it is a compound

Question 12

Every physical thing you can think of is made of which of the following?

Accepted Answer

Atoms

Answer

Cells

Answer

Molecules

Answer

Compounds

Question 13

A student claims that water is an element because it is important for life. Using your knowledge of elements and atoms, explain why this claim is incorrect.

Accepted Answer

Water is made of more than one type of atom, so it is not an element.

Answer

Water is made of only one type of atom, so it is an element.

Answer

Water cannot be broken down by chemical reactions, so it is an element.

Answer

Water is not made of atoms, so it is not an element.

Question 14

How many elements are there in total according to the learning material?

Accepted Answer

More than 100

Answer

Less than 50

Answer

Exactly 30

Answer

About 60

Question 15

According to the learning material, how many elements are important to life?

Accepted Answer

About 30

Answer

About 10

Answer

About 20

Answer

About 50

Question 16

Why is it significant that only about 30 elements are important to life, even though there are more than 100 elements?

Accepted Answer

It suggests that life depends on a small subset of elements.

Answer

It shows that all elements are equally important.

Answer

It means that elements are not important for life.

Answer

It indicates that elements are not found in nature.

Question 17

What does the diagram at the bottom of the page represent?

Accepted Answer

The periodic table of elements

Answer

A map of the world

Answer

A food pyramid

Answer

A solar system chart

Question 18

What is the central region of an atom made up of protons and neutrons called?

Accepted Answer

Nucleus

Answer

Electron

Answer

Proton

Answer

Neutron

Question 19

Which subatomic particle is positively charged and found in the center of an atom?

Accepted Answer

Proton

Answer

Electron

Answer

Neutron

Answer

Nucleus

Question 20

Which particle in the atom is neutrally charged and located in the center?

Accepted Answer

Neutron

Answer

Electron

Answer

Proton

Answer

Nucleus

Question 21

Which of the following best describes an electron?

Accepted Answer

Very small, negatively charged particle that moves around the nucleus

Answer

Positively charged particle in the nucleus

Answer

Neutrally charged particle in the nucleus

Answer

Central region of an atom

Question 22

If you were to represent the charge of a neutron, which symbol would you use?

Accepted Answer

0

Answer

+

Answer

-

Answer

*

Question 23

Explain how the location and charge of protons, neutrons, and electrons differ within an atom.

Accepted Answer

Protons and neutrons are in the nucleus and have positive and neutral charges, while electrons are outside the nucleus and have a negative charge.

Answer

Protons and electrons are in the nucleus and have positive and negative charges, while neutrons are outside the nucleus and have a neutral charge.

Answer

All three particles are in the nucleus and have the same charge.

Answer

Protons are outside the nucleus, neutrons are in the nucleus, and electrons are in the nucleus.

Question 24

Which subatomic particle is found in the nucleus of an atom and has a positive charge?

Accepted Answer

Proton

Answer

Electron

Answer

Neutron

Answer

Photon

Question 25

What is the region called where electrons are most likely to be found in an atom?

Accepted Answer

Electron cloud

Answer

Nucleus

Answer

Proton zone

Answer

Neutron shell

Question 26

Compare the locations of protons, neutrons, and electrons in an atom based on the models shown. Which statement is correct?

Accepted Answer

Protons and neutrons are in the nucleus, electrons are outside the nucleus.

Answer

Protons and electrons are in the nucleus, neutrons are outside.

Answer

Neutrons and electrons are in the nucleus, protons are outside.

Answer

All three are found only in the electron cloud.

Question 27

What is an isotope?

Accepted Answer

Atoms of the same element with different numbers of neutrons

Answer

Atoms of different elements with the same number of neutrons

Answer

Atoms of the same element with the same number of neutrons

Answer

Atoms of different elements with different numbers of protons

Question 28

How many protons are present in Carbon-12?

Accepted Answer

6

Answer

12

Answer

8

Answer

14

Question 29

How many neutrons are present in Carbon-14?

Accepted Answer

8

Answer

6

Answer

7

Answer

14

Question 30

Which of the following statements best explains why Carbon-12, Carbon-13, and Carbon-14 are considered isotopes of each other?

Accepted Answer

They have the same number of protons but different numbers of neutrons.

Answer

They have different numbers of protons and neutrons.

Answer

They have the same number of neutrons but different numbers of protons.

Answer

They have different numbers of electrons.

Question 31

What is a compound?

Accepted Answer

A substance made up of atoms of two or more elements in fixed proportions

Answer

A single element in its pure form

Answer

A mixture of any substances in any proportion

Answer

A gas that cannot be separated

Question 32

Which of the following statements is true about the physical properties of compounds?

Accepted Answer

Compounds have different physical properties than their component elements

Answer

Compounds have the same physical properties as their component elements

Answer

Compounds are always gases

Answer

Compounds cannot be separated into elements

Question 33

How many hydrogen atoms are present in a molecule of water (H2O)?

Accepted Answer

2

Answer

1

Answer

3

Answer

0

Question 34

How many oxygen atoms are present in a molecule of water (H2O)?

Accepted Answer

1

Answer

2

Answer

3

Answer

0

Question 35

Why does water (H2O) have different properties than hydrogen and oxygen gases?

Accepted Answer

Because the combination of hydrogen and oxygen in fixed proportions forms a new substance with different properties

Answer

Because it is a mixture, not a compound

Answer

Because compounds always have the same properties as their elements

Answer

Because water is not made from hydrogen and oxygen

Question 36

What does the diagram in the image illustrate?

Accepted Answer

The combination of flammable gases oxygen and hydrogen to make nonflammable water

Answer

The separation of water into hydrogen and oxygen

Answer

The mixing of two liquids to form a gas

Answer

The freezing of water into ice

Question 37

What is a covalent bond?

Accepted Answer

When two atoms share two or more pairs of electrons

Answer

When two atoms transfer electrons

Answer

When two atoms lose electrons

Answer

When two atoms gain electrons

Question 38

Each electron pair shared between two atoms forms what?

Accepted Answer

A bond

Answer

An ion

Answer

A molecule

Answer

A proton

Question 39

Why are covalent bonds important in the formation of molecules like water and methane?

Accepted Answer

They allow atoms to share electrons, creating stable molecules.

Answer

They cause atoms to lose electrons, making them unstable.

Answer

They involve the transfer of protons between atoms.

Answer

They only occur in metals.

Question 40

What happens when atoms with less than 8 valence electrons come close to each other and neither wants to give up an electron?

Accepted Answer

They share their electrons

Answer

They lose all their electrons

Answer

They form ionic bonds

Answer

They become unstable

Question 41

What type of bond is formed when electrons are shared between atoms?

Accepted Answer

Covalent bond

Answer

Ionic bond

Answer

Metallic bond

Answer

Hydrogen bond

Question 42

Why are both atoms considered 'happy' when they share electrons?

Accepted Answer

Because they both achieve a stable electron configuration

Answer

Because they lose all their electrons

Answer

Because they become negatively charged

Answer

Because they repel each other

Question 43

Based on the diagram, what is the main idea illustrated about covalent bonds?

Accepted Answer

Electrons are shared between two atoms

Answer

Electrons are transferred from one atom to another

Answer

Atoms lose all their electrons

Answer

Atoms do not interact with each other

Question 44

What is the simplest part of a substance that retains all the properties of that substance called?

Accepted Answer

Molecule

Answer

Atom

Answer

Element

Answer

Compound

Question 45

Based on the diagram, how many hydrogen atoms are present in a single water molecule?

Accepted Answer

Two

Answer

One

Answer

Three

Answer

Four

Question 46

What is an ionic bond?

Accepted Answer

A bond where one atom takes electrons from another, resulting in one positive and one negative atom that bond

Answer

A bond where atoms share electrons equally

Answer

A bond formed by overlapping orbitals

Answer

A bond that only occurs between metals

Question 47

What is an ion?

Accepted Answer

An atom that has an electrical charge to it

Answer

An atom with no electrical charge

Answer

An atom that only forms covalent bonds

Answer

An atom that cannot bond with others

Question 48

Why do atoms bond in an ionic bond?

Accepted Answer

Because one atom becomes positive and the other becomes negative, causing attraction

Answer

Because both atoms become neutral

Answer

Because both atoms lose electrons

Answer

Because both atoms gain electrons

Question 49

Explain how the transfer of electrons leads to the formation of an ionic bond.

Accepted Answer

The transfer of electrons causes one atom to become positive and the other negative, so they attract and bond.

Answer

The transfer of electrons causes both atoms to become neutral, so they repel each other.

Answer

The transfer of electrons causes both atoms to become negative, so they attract each other.

Answer

The transfer of electrons has no effect on bonding.

Question 50

Which element has 11 total electrons, 2 filled shells, and 1 extra electron?

Accepted Answer

Sodium

Answer

Magnesium

Answer

Oxygen

Answer

Fluorine

Question 51

How many extra electrons does magnesium have according to the diagram?

Accepted Answer

2

Answer

1

Answer

3

Answer

0

Question 52

What type of bond holds negative ions and positive ions together?

Accepted Answer

Ionic bond

Answer

Covalent bond

Answer

Metallic bond

Answer

Hydrogen bond

Question 53

Which of the following best describes the process shown in the diagram?

Accepted Answer

Transfer of electrons from one atom to another

Answer

Sharing of electrons between atoms

Answer

Formation of metallic bonds

Answer

Breaking of chemical bonds

Question 54

Why do atoms form ionic bonds?

Accepted Answer

To achieve a stable electron configuration by transferring electrons

Answer

To share electrons equally

Answer

To form molecules with covalent bonds

Answer

To increase their atomic mass

Question 55

Which of the following best describes a compound?

Accepted Answer

A substance made of two or more different elements chemically bonded together

Answer

A substance made of only one type of atom

Answer

A mixture of different elements and compounds

Answer

A physical blend of two or more substances

Question 56

What does the term "valence electrons" refer to?

Accepted Answer

Electrons in the outermost shell of an atom

Answer

Electrons found in the innermost shell of an atom

Answer

Electrons that are shared between atoms in a compound

Answer

Electrons that are lost during radioactive decay

Question 57

How many valence electrons does carbon have?

Accepted Answer

4

Answer

2

Answer

6

Answer

8

Question 58

Why is it important to know the number of valence electrons when studying chemical bonding?

Accepted Answer

It helps predict how atoms will bond with each other

Answer

It determines the color of the element

Answer

It tells you the atomic mass of the element

Answer

It shows the melting point of the element

Question 59

What are valence electrons?

Accepted Answer

The electrons found in the outermost shell (level) of an atom.

Answer

The electrons found in the innermost shell of an atom.

Answer

The electrons found in the nucleus of an atom.

Answer

The protons found in the outermost shell of an atom.

Question 60

How can you determine the number of valence electrons in an atom using the periodic table?

Accepted Answer

By looking at the group number.

Answer

By looking at the atomic mass.

Answer

By looking at the period number.

Answer

By looking at the atomic number.

Question 61

Refer to the periodic table diagram. If an element is in group 7, how many valence electrons does it have?

Accepted Answer

7

Answer

2

Answer

5

Answer

8

Question 62

How many valence electrons are generally needed in the outermost shell of an atom for it to be considered stable (except for Hydrogen and Helium)?

Accepted Answer

Eight

Answer

Six

Answer

Four

Answer

Ten

Question 63

Why do Hydrogen and Helium only need 2 valence electrons to be stable?

Accepted Answer

Because their first shell can only hold 2 electrons

Answer

Because they are metals

Answer

Because they have no electrons

Answer

Because they are in Group 8

Question 64

Which of the following statements best explains the stability of elements in terms of valence electrons?

Accepted Answer

Elements are stable when their outermost shell has eight valence electrons, except for Hydrogen and Helium, which are stable with two.

Answer

Elements are stable when they have an odd number of electrons.

Answer

Elements are stable when their outermost shell is empty.

Answer

Elements are stable when they have more protons than electrons.

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