Chapter 2 Flashcards
1
Q
What are isotopes? Required.
A
- Atoms of the same element which therefore have the same number of protons and electrons but a different number of neutrons
2
Q
What is the mass number of an atom, and its symbol?
A
- The total number of protons and neutrons in an atom
- A
3
Q
What is the atomic number of an atom, and its symbol?
A
- The number of protons in its nucleus
- Z
4
Q
What are cations?
A
- A positively charged ion (with fewer electrons than protons)
5
Q
What are anions?
A
- Negatively charged ions (with more electrons than protons)
6
Q
What is relative isotopic mass? Required.
A
- The mass of an isotope relative to 1/12th of the mass of an atom of carbon-12
7
Q
What is relative atomic mass (required), and its symbol?
A
- The weighted mean mass of an atom of an element relative to 1/12th of the mass of an atom of carbon-12
- Ar
8
Q
Why is relative atomic mass the “weighted mean mass of an atom”?
A
- It takes into account:
- the relative isotopic mass of each isotope
- the percentage abundance of each isotope
9
Q
What is a mass spectrometer used for?
A
- To determine relative isotopic mass
- To find the relative abundances of isotopes
10
Q
How does a mass spectrum work?
A
- Percentage abundance is shown on the y-axis
- m/z is shown in the x-axis, so for ions with one positive charge, this is equal to their relative isotopic mass
11
Q
How do you calculate the relative atomic mass of an element?
A
- (mass number of isotope 1 × abundance) + (mass number of isotope 2 × abundance), etc./ 100
12
Q
What is a binary compound?
A
- A compound that contains 2 elements only
13
Q
How are non-metals in binary compounds named?
A
- Their ending is changed to ‘ide’
14
Q
What does phosphorus exist as?
A
- P4
15
Q
Which form of sulfur is used in chemical equations, and why?
A
- Just S is used instead of S8, as otherwise everything would have to be multiplied by 8
