Atomic Structure & Chemical Bonding Flashcards
Define elements.
simplest substances, are made up from simple particles.
Define molecules.
more than one atom bonded together, can be the same type of atoms or different atoms.
Define compounds.
combinations of different types of atoms, pure substance which consists of two or more elements chemically combined.
Define atoms.
smallest part of an element that can exist chemically but not the smallest particles, (made up of protons, neutrons & electrons
Define atomic no.
smaller no.
Define isotopes.
atoms of same element with different no. of neutrons but same no. of protons.
Define electrons.
subatomic particles with a -1 charge, demonstrate wave/particle duality.
What happens when an atom absorbs energy?
e- jumps from ground state to excited state (up an energy level/s).
Give Schrodingers theory of the H atom.
properties of waves used to explain behaviour of e- in atoms
- an e- in a particular orbit is described by a wavefunction
- this model shows the nucleus surrounded by a cloud of e-
- regions of space referred to as e- or atomic orbitals where there is a high probability of finding an e-.
How are e- arranged>
atoms are arranged in successive principle energy levels.
As principle quantum no. increases, e- density…
decreases.
Give the Pauli exclusion.
each orbital has max 2 e- with antiparallel spins.
Give Hund’s rule.
max multiplicity, e- fill set a of degenerate energy orbitals by keeping their spins parallel.
Give the Aufbau principle.
to populate orbitals for a given atom, start at lowest energy orbital and work upwards.
What configuration does an atom in the ground state adopt?
configuration with the greatest no. of unpaired e-.
Describe noble gases.
- stable & inert
- monatomic
- do not normally form bonds with other elements
- do not need to gain, lose or share e- to become more stable
- fulfill Lewis Octat rule
Chemical bonds are formed between atoms with…
less than 8 e- in their valence shell, in order to make them more stable and fulfil the octat rule.
What are chemical bonds made of?
e-
Atoms must _ to form bonds.
atoms must collide with each other to form bonds.
Give the 2 types of e- in an atom.
Core & valence.
Define the 2 main chemical bonds.
-ionic
electrostatic attraction that forms between two oppositely charged ions. Ionic compounds form giant 3D lattices.
-covalent
electrostatic attraction between shared pair of electrons between atoms and the positive nuclei of those atoms. Can have up to 3 pairs of e- shared between 2 atoms.
Define electronegativity.
Ability of an atom to draw the e- from a bonding pair towards its nucleus.
What determines whether a bond is ionic or covalent?
electronegativity.
Give the features that produce a high electronegativity.
- higher nuclear charge
- small atomic radius
- low e- shielding
