Navigating the periodic table Flashcards
periodic table
system of organising the 118 known elements based on recurring patters
how did Mendeleev organise his table?
- groups vertically
- left gaps
- did not know about electron config
elements with same valence electrons?
same properties
matter
atoms bonded together
reactions happen when…
bonds between atoms break and reform in new arrangements
what are involved in bonds?
electrons
core electrons
inner electrons that do not bond
how are electrons arranged in shells?
2, 8, 8, 18, 18, 32, 32
why does a full shell make an atom stable?
lots of energy required to remove or add electrons
ionic bonds - define and what do they form?
what type of bond is it?
one elements gives up an electron (cation) and one accepts (anion). they are attracted to their opposite charges and form a lattice.
electrostatic
covalent bonds
the sharing of electrons between atoms. some can share multiple ways.
define molecule
groups of atoms that share electrons covalently
cation + anion =
salt
how is the cation named?
as the element is eg. magnesium
how is the anion named?
one element ends in ide
if there is an oxygen it is ite or ate
what shields nucleuses from each other in covalent bonding?
electrons
what are the electrostatic interactions in covalent bonding?
attraction - between electrons and nucleus
repulsion - between electrons and between nuclei
how to name covalent bonds?
first element is just its name
second takes the stem of the name and adds ide
prefixes indicate number of atoms
bonding continuum?
more of a continuum then ionic and covalent
explain how bonds break and from
- making bonds releases energy (lower energy arrangement)
- breaking bonds requires energy (pull)
- net energy released from bond formation
how does electronic configuration work?
nS^2np^6
n is shell number
s, p, d are the orbitals
numbers are number of electrons
What are formal charges and what do they need to be?
- a representation of how charge is distributed
- needs to be 0 or close
- in a neutral molecule all atoms should be 0
equation for formal charge
FC = number of valence electrons central atom has - (number of lone pairs + 1/2 bonding electrons)
steps for drawing lewis diagrams
- determine number of valence electrons
- arrange atoms around a central atom and give each atom set a single bond
- beginning with terminal atoms, add enough electrons to each atom to give the atom an octet
- place any left over electrons on central atom
- minimise formal charges by making double and triple bonds
