1. Atoms and Molecules

Question 1

Definition of Biology

Answer 1

Biology - the study of living organisms that are subject to the laws of chem and phys

Question 2

Key concepts about atoms and molecules in biology

Answer 2

1. Matter consists of chem elements in pure form / combinations called compounds
2. An element’s properties depend on the structure of its atoms
3. Formation + function of molecules depend on chemical bonding between atoms
4. Chemical reactions make and break chemical bonds

Question 3

Define element

Answer 3

Element - a substance that cannot be broken down into another substance by a chemical reaction

Question 4

Define compound

Answer 4

Compound - substance consisting of 2+ different elements combined in a fixed ratio

Question 5

What are the biological elements and how many % of living matter do they make up?

Answer 5

C, H, O, N

96%

Question 6

Define atom

Answer 6

Atom - the smallest unit of an element that retains the chemical properties of the element

Question 7

Explain the structure of an atom

Answer 7

Nucleus = protons + neutrons (same # as protons unless isotope) -> atomic mass
Electrons in atomical orbitals -> little weight - not considered, same # as protons

Question 8

Define potential E

Answer 8

Potential E - E that matter possesses because of its location / structure

Question 9

Which parts of an atom are involved in chemical reactions?

Answer 9

Only electrons - those atoms reactive which have unpaired e- in the valence shell

Question 10

What is the source of potential E in e?

Answer 10

Distance from the nucleus - the greater potential E as the e- moves further form the nucleus

Question 11

Which E state is preferred by matter?

Answer 11

Matter moves to the lowest state of E

Question 12

What determines chemical behaviour of an atom?

Answer 12

Determined by the distribution of e- in e- shells

Question 13

Define covalent bond

Answer 13

Covalent bond - sharing a pair of valence e- by two atoms

Question 14

How are e- distributed in ionic bonds?

Answer 14

More EN atoms completely removes e- from less EN atom

Question 15

The types of ions

Answer 15

Atoms or molecules can be ions

Question 16

Define crystal

Answer 16

Crystal - an aggregate of cations and anions bonded by their electrical attraction and arranged in 3D lattice

Question 17

RLE of Van der Waals forces

Answer 17

Gecos can slide on water due to forces between molecules on their limbs and water surface