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Flashcards in Lecture 1 Deck (25):
1

Nucleus includes: (2)

- Neutron
- Proton

2

Electrons (4)

- occupies large space
- occupies in shells
- inner shell has max 2 e-
- outer electrons, aka outermost shells

3

Why is carbon 12.03?

- because of isotopes

4

What is isotopes?

same # of electrons, different neutrons

5

What are isotopes used for?

- imagining, radiocarbon dating

6

Radiocarbon dating

use to determine the dead, fossils and how long these bones last for

7

Mass number (He 4 or 2)

- top # (4)
- # of protons + neutrons

8

atomic number

- number of protons

9

All life depends on what in the atmosphere?

- carbon dioxide

10

Archeology

- the study of human activity through the recovery and analysis of material culture
- takes bones and grind them, see how much C14 are in these bones.

11

If bones have the same amount of C14 as in the atmosphere, what does that mean?

- recent bone
once u die, the exchange of CO2 stops, C14 starts to decay, gets less and less overtime

12

What causes the formation of chemical bonds?

To link atoms tgt, to form chemical bonds, only electrons are important.

13

What elements mostly made up our body? (4)

- hydrogen
- carbon
- nitrogen
- oxygen

14

Periodic table (group)

same amount of e- in the outer most shell, meaning that they are similar chemistry

15

Rows (period)

all the amount in the same rows are roughly the same size, because of the same # of shells

16

Three types of bond

- covalent bond
- ionic bond

17

Covalent bond (3)

1. A covalent bond is made of 2 electrons
2. These 2 electrons are shared, i.e. one electron comes from each atom
3. Atoms can form bonds until their outermost shell is filled

18

What is so special about central atom?

95% probability of where e- are

19

What is nonpolar covalent bond?

Electrons are shown to be superimposed
on the bond to indicate that they are
halfway between the two atoms, shared
equally

20

Polar covalent bonds

Electrons are not shared equally
(O is more electronegative than
H), so partial charges exist on
the O and H atoms
Polar = shared unequally, e- spend more time on the oxygen

21

Trends of electronegativity

The higher the electronegativity, the stronger the attraction

22

Valence electron

number of unpaired electrons

23

What is so special about hydrogen bond? (2)

- A meniscus forms where water meets a solid surface,
as a result of two forces.
- high surface tension
- in trees, water can rise up to the top because of hydrogen bond, force that push the water up (evaporation) coz of hydrogen bond
- (a) In ice, water molecules form a crystal lattice.
- (b) In liquid water, no
crystal lattice forms.
- (c) Liquid water is denser than ice. As a result,
ice floats.

24

Adhesion: Water

Water molecules that adhere to the glass resist the downward pull of cohesion

25

Cohesion: Water

Water molecules at the surface experience a net downward pull from hydrogen bonds with water molecules below