Chapter 2 - Chemistry and Biology

Question 1

in an atom, protons have a ____ charge and neutrons have a _____ charge and the electrons have a _____ charge

Answer 1

positive, neutral, negative

Question 2

in the nucleus of an atom, what two main subunits are together?

Answer 2

protons and neutrons

Question 3

which subunit of the atom roams outside of the nucleus?

Answer 3

electrons

Question 4

what is the process called when elements interact with other elements because they want to fill their valence shell with more electrons?

Answer 4

its called covalent bonding in which atoms temporarily by sharing electrons

Question 5

what are the four most important elements in biology?
how much percentage of our body do they comprise of?

Answer 5

COHN - Carbon, Oxygen, Hydrogen, Nitrogen
96%

Question 6

what elements comprise 4% of the human body

Answer 6

calcium, phosphorus, potassium, sulfur, magnesium, sodium, chlorine,

Question 7

what happens if the number of protons change in an element?
why?

Answer 7

The element changes as well
The number of protons in an element is unique to each element hence the protons act as an identification card

Question 8

what happens to the identity of the element if the neutrons of two elemental atoms are different?
Is there a label/definition to this situation?

Answer 8

Nothing happens to their identities as difference in neutrons of the same atom doesn’t change their identity.
These are called isotopes.

Question 9

what does it mean when an element is a radioactive isotope?
what two things is it cont. losing?

Answer 9

it means that the isotope is decaying continuously
it is cont. losing electrons and energy

Question 10

how can radioactive isotopes will functional? list three ways

Answer 10

1. They help date fossils’ ages
2. They trace the atoms through metabolic processes - helping monitor those processes
3. They can help diagnose any abnormality or disorders because of how they can be traced.

Question 11

can radioactive isotopes be replaced in place of their normal elements such as Carbon-12 to Carbon-14?

Answer 11

Yes.

Question 12

how can we predict the chemical behavior of an atom?
- why can we predict it?

Answer 12

by looking at their valence electrons in the valence shells.
because since atoms want to be stable and have 8 valence electrons, they often bond with other elements in order to temporarily borrow these electrons

Question 13

how do atoms bond with one another?
- explain the bond briefly

Answer 13

through chemical reactions namely covalent bonds.
Covalent bonds are temporary bonds that occurs when one atom shares/accept electrons in their valence shell with another atom

Question 14

do some atoms act more possessively with the shared electrons of the covalent bonds?
What is this concept called?

Answer 14

Yes, this concept is called electronegativity which pulled the electrons more or less strongly based on how many electrons they originally have

Question 15

what terms applies to the covalent bond when it is affected by electronegativity?

Answer 15

The term is called polar covalent bond

Question 16

what terms applies to the covalent bond when it is NOT affected by electronegativity?

Answer 16

Nonpolar covalent bond

Question 17

what is it called when atoms completely take away the electrons from another atom?

Answer 17

Ionic bond

Question 18

what happens to the atoms when an ionic bond forms?

Answer 18

each of them becomes charged with either a positive or a negative charge

Question 19

what do we call a positively charged atom?

Answer 19

cation

Question 19

what is hydrogen bonding?

Answer 19

hydrogen atom bonded to two electronegative atoms due to their strong electronegativity

Question 19

what do we call a negatively charged atom?

Answer 19

anion

Question 20

explain the concept of van der waals attraction between two atoms

Answer 20

this type of attraction occurs between two atoms who are attracted mainly due to the proximity near each other

Question 21

Do ionic bonds dissolve in water? Why?

Answer 21

Because the attraction from the molecules of water is so high, the ionic bonds break and instead, these molecules covalently bond with water

Question 22

when does a set of reactants and products reach chemical equilibrium?

Answer 22

when the concentration of reactants and products are the same even when reversed

Question 23

what is considered a chemical reaction? give an example

Answer 23

when two atoms make and break covalent bonds, such as two elements mixing to become a new substance in a chemical tube.

Question 24

which bond between two atoms is the strongest?
- Ionic
- Hydrogen
- Van der Waals
- Covalent
- Non covalent

Answer 24

Covalent Bond