Atomic structure Flashcards
who discovered that atoms were the smallest building blocks of matter?
ancient greeks and John dalton
who discovered electron and plum pudding model?
JJ Thompson
who discovered neutron?
Chadwick
Discovery of the nucleus? and how?
rutherford
bombarded gold foil with alpha particles and found that particles scattered. allowed to deduce that there is a positive nucleus repelling and colliding with particles.
discovery of arrangement of electrons
Bohr
define Atomic number
the number of protons in an atom of an element
define mass number
the total number of protons and neutrons inside the nucleus of an atom
define nucleons
protons and neutrons collectively in a nucleus
define relative atomic mass
It is the mass of a particle on the scale where an atom of carbon-12 has a mass of 12
define isotopes
Atoms of the same element having the same number of protons, but different number of neutrons
define Hunds rule
Every orbital in a sub-level is singly occupied by electrons before any orbital is doubly occupied
define paulis exclusion principle
Orbitals can accommodate a maximum of 2 electrons provided they spin in opposite directions
define valence electrons
electrons in the outermost energy level of an atom that can participate in the formation of chemical bonds
define orbitals
area in space surrounding the nucleus where an electron is most likely to be found
what is Z
smaller number
atomic number and number of protons
and number of electrons
what is A
bigger number
mass number
neutrons + protons
3 isotopes of hydrogen and their neutrons
protium- 0 neutrons
deuterium- 1 neutrons
Tritium- 2 neutrons
what is different in isotopes and what is the same?
everything same besides number of neutrons
explain how to get relative atomic mass of isotopes
- write down the isotopes and their percentages
- Ar= put percentages over 100 and multiply by their mass number
- do this for all and add
- unitless answer
explain how to calculate percentage abundance of isotopes?
- write down isotopes and name smaller one p and other one 100-p
- RAM= put p over 100 and multiply by mass number and put 100-p and multiply by mass number
- add together and solve equation
- write down the percentage abundance for each
why do isotopes of an element have similar characteristics?
isotopes have same number of electrons, electrons involved in bonding. same number of electrons means same reactivity.
energy of electrons close to nucleus?
low
energy of electrons further away from nucleus?
high
what does aufbau diagrams show
that within each energy shell there are orbitals at different energy levels
draw aufbau template
increasing energy (vertical) 4s // 3p. // // // 3s // 2p. // // // 2s// 1s//
define atomic orbital
region in which an electron may be found around a singe atom
what is SP notation
electronic configuration- shortened version of aufbau diagrams
