Bonding, Structures And Properties Flashcards
what is an isotope
any of two or more forms of an element, that have the same number of protons and the same atomic number, but having different numbers of neutrons and therefore different atomic weights.
so they have the same chemical properties but different physical properties.
what is an ionic bond?
ionic bonds are formed between a metal and a non-metal. the metal loses electrons from its outer shell you form positive ions and the non-metal gains electrons to form negative ions.
what happens as the group number increases in the periodic table? ( more in outer shell)
there are more elections in the outer shell so the less reactive they get.
what happens to reactivity as you go down the groups?
They get more reactive as you go down because the outer electrons are further away from the nucleus
what is a covalent bond?
it is between two non-metals and they share the electrons instead of giving and taking.
e.g water
in the periodic table,
what us the top number?
what is the bottom number?
top=mass number
bottom=atomic number
what is the structure of an ionic compound?
a huge lattice of positive and negative ions packed together in a regular arrangement.
what are 3 properties of ionic compounds?
and why?
HARD SUBSTANCE- they consist of a regular pattern of opposite ly charges ions with strong bonds between them.
BRITTLE- any small distortion of crystal brings ions with the same charge together. Same charges repellent so the crystal splits apart.
HIGH MELTING POINT- due to strong forces of attraction holding the latuce together.
what factors affect the strength of an ionic bond and thus it’s melting point?
attractive forces are stronger between certain atoms and compounds if they have a higher charge (2+) than (1+)
why do most ionic compounds dissolve in water?
because water molecules are able to break down the ionic bonds between the opposite ly charged ions
why do ionic compounds in the solid state not conduct electricity.
the ions are held in a fixed position by strong forces of attraction.
why do ionic compounds in a molten state or aqueous solution conduct electricity
the ions are free to move and carry charge
what happens to the rate or reaction if you increase the surface area?
it will increase, as it gives particles a bigger area of solid reactant to react with.
what happens when a catalyst is added? and why?
it speeds up the reaction but is itself chemicals unchanged at the end. as the catalyst provides an alternative pathway for a reaction with a lower ‘EA’ (activation energy).
if you increase the pressure of a gasses reaction what happens to the rate of reaction? and why?
the rate or reaction increases, as there are more particles in a given area, so more chance of successful collisions.
