Topic 1 week 1 Flashcards
What does the atomic number tell us?
The number of protons in the nucleus and the number of electrons in an electrically neutral atom
In a neutral atom what is the relationship between protons and electrons
The charge is equal
How do you figure out mass number (atomic mass)?
Total number of protons and neutrons in a single atom
What is atomic mass a measure of?
The mass of a single atom relative to the mass of a single proton
What is the mass of a single proton and a single neutron
1 amu
How do you work out the mass of a molecule
Add all the atomic weight values of the atoms in the molecules
What is an isotope
same number of protons different number of neutrons in their nucleus
Define relative atomic mass (atomic weight)
The ratio of the average mass of all atoms of an element
Relative to 1/12th of the mass of a carbon atom
Calculated from the atomic mass and abundance of each isotope
Give the equation for RAM
sum(abundance x atom mass)
What is molecular orbital theory
It suggests the probable distribution of electrons
What are core electrons
Inner electrons that are not used in forming chemical bonds
What are valence electrons
Outer shell electrons always and only- some or all are involved in forming chemical bonds with other atoms
How did Mendelev organise the periodic table
By increasing atomic mass
Elements with properties clustered
Gaps that predicted other elements exist
What did William Ramsey discover
discovery and placing of inert noble gases into group zero of the periodic table
What did Alfred Werner discover
the placing of lanthanoids in a separate block
