Module 2 - random stuff to remember Flashcards
What is an isotope?
Atoms of the same element but with different numbers of neutrons and mass numbers
Why do isotopes not differ in chemical properties?
Electrons are responsible for chemical properties and isotopes have the same number of electrons
Why do isotopes differ in physical properties?
More neutrons:
- Higher mass
- Higher MP and BP
- Higher density
What is relative isotopic mass (Mr)
Mass of an isotope relative to 1/12th of the mass of an atom of carbon-12
What is relative atomic mass (Ar)
Weighted mean mass of an atom of an element relative to 1/12th of the mass of an atom of carbon-12
mol dm-3 —> g dm-3
x Mr
g dm-3 —> mol dm-3
÷ Mr
cm3 —> m3
x 10-6
What is a standard solution?
A solution with a known concentration
What is a limiting reagent?
Reactant that is NOT in excess and will be completely used up first so will stop the reaction
How to calculate number of electrons present in each shell?
2n2 where n is shell number
What does the strength of the ionic bond depend on?
Size and charge of ions involved
What two factors give a strong ionic bond?
Greater charge
Small ions
How many covalent bonds can boron form?
Three (only 6 electrons in outer shell)
How many covalent bonds can phosphorus, sulfur and chorine form?
Up to six (can have 18 electrons in outer shell as they have d-sub shell)
