Basic Chemistry Flashcards
Lecture 01 and 02
1
Q
atomic number
A
- number of protons
2
Q
atomic mass
A
- number of protons + neutrons
3
Q
changes moving across the periodic table
A
- nuclei gets bigger as an extra proton is added to the element
- each atom will have an extra electron
- increasing size of the nucleus means a bigger pull on electrons (electronegativity)
4
Q
ionisation energy
A
- energy needed to remove electrons
- increases from left to right
5
Q
metals
A
- lose electrons to become positively charged ions
6
Q
non-metals
A
- gain electrons to become negatively charged ions
7
Q
changes moving down the periodic table
A
- nuclei gets bigger
- increase in electrons
- with each row/period there is an extra shell to fill
- each successive electron shell effectively shields the electrons from the pull within the nucleus from protons
8
Q
stability
A
- atoms are most stable when their outer electron (valence) shell is full through either loss or gain
9
Q
ionic bonding
A
- loss or gain of electrons to achieve a full outer shell
- between metals and non-metals
10
Q
covalent bonding
A
- between non-metals
- too close = nuclei repel each other
- too far apart = no attraction
- bond length = 0.074nm
11
Q
when do covalent bonds form
A
- when atoms are not readily ionisable
12
Q
molecular orbitals
A
- formed where shared electrons occupy the atomic orbitals of each atom involved
13
Q
hydrogen bonding
A
- weak chemical bonds
- 1/20th of the strength of a covalent bond
14
Q
when are hydrogen bonds formed
A
- when a H atom covalently bonded to one electronegative atom is attracted to another electronegative atom
15
Q
what are hydrogen bonds formed between
A
- H and O
- H and N
16
Q
van de waals
A
- weaker than hydrogen bonds
- electrons in motion with an uneven distribution of charges
17
Q
opposite charges
A
- attract
18
Q
like charges
A
- repel
19
Q
valence shell
A
- outer shell
20
Q
what percentage of a cell is made of water
A
- 70%
21
Q
what is water
A
- a solvent where many hydrophilic solutes are dissolved
- cellular reaction occur here
22
Q
what kind of bonding does water have
A
- covalent
- uneven distribution of charge = high electronegativity for oxygen
23
Q
electronegativity
A
- a chemical property that describes the tendency of an atom or a functional group to attract electrons toward itself
24
Q
is water a polar or a non-polar molecule
A
polar
25
water cohesion
- interaction between molecules
26
2H2O
OH- and H3O+
27
hydrophilic molecules
- readily dissolve in water
28
ionic
- large charges which attract smaller uneven charges of water molecules
29
polar
- molecules with an uneven distribution of charge e.g., urea
30
examples of polar bonds
- O-H
- O-N
31
hydrophobic molecules
- do not dissolve in water
- non-polar
- water molecules attracted to each other rather than non-polar molecule
32
examples of non-polar molecules
- C-H
- used to create cell membranes
33
carbon
- can form single or double bonds with other atoms
34
single bonds
- 2 shared electrons
35
