periodic table & bonding Flashcards
how many electrons can fill the 1st shell
2
how many electrons can fill the 2nd shell
8
how many electrons can fill the 3rd shell
8
group 0 elements are inert, what does this mean
they dont react with much at all
how do ions form
when an atom loses or gains an electron
when are negative ions formed
when an atom gains an electron
when are positive ions formed
when an atom loses an electron
how are ionic compounds formed
-when a metal and a non metal react together
-the metal forms a positive ion and the non metal forms a negative ion
-the electrostatic attraction between oppositely charged ions forms an ionic bond
what is the structure of an ionic compound
giant ionic structure
in ionic compounds, how are ions held together
in a 3d lattice arrangement
why do ionic compounds have high melting and boiling points
-a lot of energy is needs to overcome the strong attraction between oppositely charged ions
what are the properties of ionic compounds
-not electrical conductors when solid
-conduct electricity if melted or dissolved in water
what is covalent bonding
where atoms bond by sharing pairs of electrons
what does each covalent bond provide
one extra shared electron
describe the electrostatic attraction in covalent bonding
it is between negatively charged shared electrons and positively charged nuclei
describe the bonds in a simple molecular substance
-the atoms are held together by strong covalent bonds
-the forces of attraction between the molecules are very weak
-so melting and boiling points are low
describe the bonds in a giant covalent structure
-all atoms are bonded by strong covalent bonds
-there are lots of these bonds meaning a lot of energy is needed to break them
-so giant covalent structures have high melting and boiling points
what are the properties of giant covalent structures
-dont conduct electricity
-insoluble in water
-e.g diamond and graphite
what is electric current
flow of electrons or ions
when do ionic compounds conduct electricity
when molten or in solution
what happens to the conductivity of ionic compounds when they melt
the ions move so the compound can conduct electricity
what is metallic bonding
the electrostatic attraction between the nuclei of the positive ions and the electrons
why are metals good conductors of electricity and heat
the delocalised electrons can move
why are metals malleable
the layers of ions can slide
