Atomic Structure Flashcards
What is an element made up of
Very small and heavy nucleus contains protons and neutrons (nucleons) and carries most of the mass
Proton mass
1
Electron mass
1/1840
Neutron mass
1
Charge of proton
+1
Charge of neutron
0
Charge of electron
-1
Atomic Number
Proton number
Mass Number
Proton number + nucleon number
Atoms only:
Number of proton == number of electron
What is an electrically neutral atom
number of protons == number of neutrons
When is an ion formed
number of protons != number of electrons
Number of neutrons
mass number - number of protons
What is a valence shell
Outermost shell of the atom, occupied by electrons
full atom symbol
chemical symbol of element
top left: mass number/nucleon number
bottom left: proton number/atomic number
How to draw electronic structure
- Start with nucleus and chemical symbol
- Based on number of electrons, draw the electrons on the shells
Up to 20: 2, 8, 8, 2
What are valence electrons
electrons residing in the outermost shell of the atom
What does group number show (Groups 1,2)
(For Groups 13 - 18, -10)
number of valence electrons
What does period number show(Groups 1,2)
(For Groups 13 - 18, -10)
number of occupied electrons shell
Why do elements in the same period have the similar chemical properties
elements in the same period have the similar chemical properties as they have the same number of valence electrons
What are isotopes
Atoms of the same element with the same number of protons but different number of neutrons
Isotopes have same proton number/atomic number but different mass number/nucleon number
Not all elements have isotopes and not all isotopes are present in equal proportion
Sum of relative abundance of all isotopes for one element is 100%
Why do isotopes of the same element have the same chemical properties
isotopes of the same element have the same chemical properties as they have the same number of electrons
however they have different physical properties
What is relative atomic mass
average mass of an atom, taking into account different natural occurring isotopes and their relative abundance
