Chapter 2 Atoms Ions and Compounds Flashcards
What does an atom consist of
A nucleus made of protons and neutrons
What is the relative charge and relative mass of a proton
1+
1
What is the relative charge and relative mass of a neutron
0
1
What is the relative charge and relative mass of an electron
1-
1/1836
What are elements
A substance made up of only one type of atom
What identifies the element
The number of protons in an atom
What is the atomic number (Z)
The number of protons in the nucleus of an atom
What is an isotope
Atoms of the same element with different numbers of neutrons
Do isotopes of the same element react in the same way
Yes
What is the relative isotopic mass
The mass of an isotope compared with 1/12th of the mass of an atom of carbon-12
What is the relative atomic mass
The weighted mean mass of an atom compared with 1/12th of the mass of an atom of carbon-12
How can the percentage abundances of isotopes and their relative isotopic masses be found experimentally
Using a mass spectrometer
How does a Time-of-flight mass spectrometer work
- Sample is vaporised and
then ionised to form
positive ions:
X(g) + e- → X+(g) + e- + e- - Ions are accelerated to the same kinetic energy
- Ions are separated according to their mass. Heavier ions move more slowly and take longer to reach the detector than lighter ions
How do you work out Ar
Σ (percentage abundance x relative isotopic mass) / Σ percentage abundance
Based on the line in the periodic table, which atoms lose electrons and which atoms gain electrons
- Atoms on the left lose electrons to form positive ions (cations)
- Atoms on the right gain electrons to form negative ions (anions)
