Atomic Structure Flashcards
1
Q
What name do we give to the type of attraction between the positive protons and negative electrons?
A
- electrostatic
2
Q
What is atomic number Z?
A
- amount of protons
3
Q
What is the mass number A?
A
- amount of protons + neutrons
4
Q
What is an isotope
A
- atoms of the same element with the same amount of protons but different amount of neutrons
5
Q
What is relative atomic mass (Ar)
A
- average mass of an atom of an element relative to 1/12th the mass of an atom of carbon-12
6
Q
What is relative molecular mass (Mr)
A
- average mass of a molecule of an element relative to 1/12th the mass of an atom of carbon-12
7
Q
What is isoelectronic
A
- same electronic configuration
8
Q
How does electron impact ionisation work?
A
- high energy electrons fired at vaporised sample
- one electron is knocked off forming an M+ ion
9
Q
How does electrospray ionisation work?
A
- the sample is dissolved in a volatile solvent and forced through the end of a hypodermic needle
- needle attacked to the positive terminal of a power supply
- particles gain a proton as they leave the needle forming a MH+ ion
10
Q
How are the particles accelerated?
A
- the positively charged species are attracted to a negatively charged accelerating plate
11
Q
Describe the process of detection
A
- the positive ions hit the detector plate and gains an electron
- this generates a current and the size of the current is proportional to the abundance of the ion
12
Q
What is a molecular ion
A
- the molecule with one electron knocked off
OR - the ion with the largest m/z (value/ratio)
13
Q
What is high resolution mass spectrometry?
A
- allows us to see the exact masses of isotopes if different elements
14
Q
Chemical bonds are always…
A
- bending
- stretching
- vibrating
15
Q
Every type of bond has its own…
A
- unique natural frequency that is in the infrared region of the EM spectrum
16
Q
What happens when infrared radiation is passed through a sample of a compound?
A
- certain frequencies are absorbed depending on the bonds which are present
- these frequencies are not detected and therefore we get peaks
17
Q
What does an acidic O-H bond look like?
A
- very broad peak between 2500-3000
18
Q
What does an O-H bond in alcohols look like
A
- broad peak between 3230-3550
19
Q
What does a C=O bond look like?
A
- long sharp peak between 1680=1750
20
Q
What is the fingerprint region?
A
- region of an infrared spectrum below 1500 - unique to every compound
