1.1 Fundamental Chemistry of Life

Question 1

What is an element in the context of chemistry?

Answer 1

An element is a pure substance that cannot be broken down into simpler substances.

Question 2

raWhat is a chemical compound?

Answer 2

A stable combination of different elements held together by chemical bonds.

Question 3

Which four elements make up 96% of the weight of a living organism?

Answer 3

Carbon (C), hydrogen (H), oxygen (O), and nitrogen (N).

Question 3

How are radioisotopes useful in medical diagnostics?

Answer 3

Radioisotopes are used in medical diagnostics to image organs and diagnose conditions. For example, radioactive iodine-131 is used to scan the thyroid gland to identify issues with thyroid hormone levels.

Another example is PET scans. During pet scans, a small amount of radioactive glucose (which contains radioisotopes) is inserted into the body. Because cancerous cells absorb more glucose than the average cell, it is easy to locate tumours within the body.

Question 4

What is an isotope?

Answer 4

An isotope is a different form of the same element with a different number of neutrons and therefore a different atomic mass.

Question 5

What are the three subatomic particles of an atom, and where are they located?

Answer 5

Protons and neutrons are located in the nucleus, while electrons are located in the region surrounding the nucleus.

Question 6

What is a radioisotope, and how is it formed?

Answer 6

A radioisotope is an unstable isotope that decays. The nuclei of some isotopes of elements are unstable. They break off, and emit radiation as they break down. These are called radioisotopes.

Question 7

What is the role of radioactive tracers in scientific research?

Answer 7

Radioactive tracers are used to follow the path of specific chemicals through reactions and processes in biological and chemical research.

Question 8

What is the difference between valence electrons and core electrons?

Answer 8

Valence electrons are the electrons in an atom’s outermost energy shell, while core electrons are in the inner shells. Valence electrons are involved in chemical bonding and reactions.

Question 8

Why are atoms with unfilled valence shells more reactive?

Answer 8

Atoms with unfilled valence shells are more reactive because they tend to interact with other atoms to complete their outermost shell, either by gaining, losing, or sharing electrons.

Question 8

Why are some elements, like calcium and phosphorus, crucial for living organisms?

Answer 8

Elements like calcium and phosphorus are important for various biological functions, including bone structure (calcium) and energy storage (phosphorus in ATP).

Question 8

What is an ionic bond, and how does it form?

Answer 8

An ionic bond is the attraction of opposite charges. It forms between atoms that have lost or gained electrons to become charged ions. Oppositely charged ions attract each other to form an ionic bond.

Question 9

What is a covalent bond, and how is it different from an ionic bond?

Answer 9

A covalent bond is the sharing of an electron pair; when atoms share one or more pairs of valence electrons. Whereas an ionic bond forms through the electrostatic attraction between oppositely charged ions. Covalent = sharing of electrons, Ionic = full transfer of electron(s)

Question 9

How are non-polar covalent bonds different from polar covalent bonds?

Answer 9

Non-polar covalent bonds occur when atoms with similar electronegativities share electrons equally, whereas polar covalent bonds occur with unequal sharing due to different electronegativities.

Question 10

How does electronegativity affect covalent bonding?

Answer 10

The more electronegative an atom, the more strongly it attracts shared electrons, leading to polar covalent bonds if there is a significant difference in electronegativity.

Question 11

What are hydrogen bonds?

Answer 11

Hydrogen bonds are attractions that occur when a hydrogen atom, covalently bonded to a highly electronegative atom (such as oxygen, nitrogen, or fluorine), is attracted to another electronegative atom in a different molecule.

Question 11

What are van der Waals forces?

Answer 11

Van der Waals are interactions of electrons of nonpolar substances. They are weak intermolecular forces of attractions between molecules, caused by temporary or permanent dipoles in molecules. (ex. 2 CH4 molecules would have a weak van der waals attraction since both are nonpolar)

Question 12

What creates a polar covalent bond?

Answer 12

A polar covalent bond is created when two atoms with different electronegativities share electrons unequally, resulting in partial charges on the atoms.

Question 13

How do van der Waals forces differ from hydrogen bonds?

Answer 13

Van der Waals forces are generally weaker and result from temporary attractions between molecules, while hydrogen bonds are stronger and involve permanent dipole attractions.

Question 14

What is a dehydration reaction?

Answer 14

A dehydration reaction removes water to join molecules, forming larger macromolecules like proteins and carbohydrates.

Question 15

What is a hydrolysis reaction?

Answer 15

A hydrolysis reaction uses water to break down larger molecules into smaller subunits.

Question 16

What happens in a neutralization reaction?

Answer 16

In a neutralization reaction, an acid and a base react to form a salt and often water.

Question 17

What is a redox reaction?

Answer 17

A redox reaction involves the transfer of electrons between atoms, with one atom being oxidized (losing electrons) and another being reduced (gaining electrons).

TIP: OILRIG –> Oxidation Is Losing electrons, Reduction Is Gaining electrons.

Question 18

What does oxidation refer to in a redox reaction?

Answer 18

Oxidation refers to the loss of electrons from a molecule or atom, resulting in an oxidized molecule or atom.

Question 19

What does reduction refer to in a redox reaction?

Answer 19

Reduction refers to the gain of electrons by a molecule or atom, resulting in a reduced molecule or atom.

Question 20

What is the role of the oxidizing agent in a redox reaction?

Answer 20

The oxidizing agent is the molecule or atom that is being reduced (gaining electrons) in the reaction.

Question 21

What is the role of the reducing agent in a redox reaction?

Answer 21

The reducing agent is the molecule or atom that is being oxidized (losing electrons) in the reaction.

Question 22

What are the two classes of interactions of molecules?

Answer 22

Intermolecular forces (between), which is physical.
Intramolecular forces (within), which is chemical.

Question 23

What is considered intermolecular forces?

Answer 23

Hydrophobic interactions, hydrogen bonds, and Van der Waals

Question 24

What is considered intramolecular forces?

Answer 24

Ionic and covalent bonds

Question 25

List the differences of electronegativity numbers

Answer 25

0-0.4 = nonpolar
0.4-1.0 = moderately polar
1.0-2.0 = polar
2.0≥ = ionic

Question 26

The two general rules of determining if a molecule is polar or nonpolar

Answer 26

1. Different atoms around a central atom will always be polar
2. Same atoms around a central atom will always be nonpolar

Question 27

What are the diatomic elements?

Answer 27

HOFBrINCl, all of which are nonpolar!