Unit 1 The periodic table Flashcards
Define relative/natural abundance
Is a consistent ratio found in nature for given elements.
What is atomic mass of an element?
Is the weighted average of the mass of its isotopes.
Define weighted average
means some values have greater impact of the average than others.
What are some important points when calculating relative abundance?
- the larger isotope number is “x”
- the first step to isolating “x” is to multiply both sides by 100
What are the two rules that need to be followed for adding electrons to the orbital box diagrams?
1) Pauli Exlusion Principle
2) Hund’s Rule
Describe the two rules for the orbital box diagram
Pauli Exclusion Principle:
- The maximum number of electrons in each orbital is two. If two electrons are in one orbital, they must have opposite spins.
Hund’s rule:
- When adding electrons to a sublevel with more than one orbital, the electron spins must be all the same until each orbital has one electron.
What is the Aufbau principle?
Electrons fill sublevels starting with the lowest energy level up to highest energy.
State the limitations of the Bohr Model
Assumes or suggests:
- electrons orbit the nucleus/is predictable
- shape of orbits/shells are all spherical
- an incorrect scale of an atom
- energy of electrons in a level are all the same
What are the exceptions to the full electron configuration?
- Nearly full “d” sublevels will take an electron from the closest “s” sublevel to be full
- Nearly half full “d” sublevels will take an electron from the closest “s” sublevel to be half full
What is the electromagnetic spectrum order in increasing energy?
Radiowaves, Microwaves, infrared, visible, untraviolet, x-rays, gamma rays
How are the elements of the periodic table arranged?
By increasing atomic number
What is the significance of the periodic groups?
The elements in the groups have similar chemical properties.
- same number of valence electrons
What is the name of group 1?
Alkali metals
What is the name of group 2?
Alkaline earth metals
What is the name of groups between group 2 and 3?
Transition metals
What is the name of group 6?
Chalcogens
What is the name of group 7?
Halogens
What is the name of group 0 (or 8)?
Nobel gasses or inert gasses
What is the name of the two lower rows?
Rare earth elements
What are the horizontal rows called and what is their significance?
Called periods
- the number of the period equals the number of energy levels in the ground state
What is Atomic Radius?
The distance from the nucleus to the outermost electron.
How do you find atomic radius?
Half the distance nuclei of two bonded atoms of the same element (ex. diatomic molecules)
- is estimated for non-identical atoms
What is Ionic Radius?
Defined as the distance from the nucleus to the outermost electron of an ion
Describe on general terms the ionic radius of the ions
- Cations loose electrons and are smaller than their respective atom, occurs for metals.
- Anions have gained electrons and are larger than their respective atom, occurs for non-metals.
Define First Ionization Energy
The energy needed to remove one electron from an atom in its gaseous state.
Define electronegativity
Is a relative measure (having no units) of the attraction an atom has for a pair of electrons that are shared with another atom.
Define electron affinity
The energy released when one electron is added to an atom in its gaseous state. (only applies to non-metals)
What is the periodic trend for atomic radius?
Atomic Radius:
- increases down the group because an extra shell is added
- decreases across the period because there are more protons
What is the periodic trend for ionic radius?
Ionic Radius:
- increases down the group because an extra shell is added
- decreases across the period because there are more protons
What is the period trend for ionization energy?
Ionization Energy:
- decreases down the group because an extra shell is added
- generally increases across the period because there are more protons
What is the periodic trend for electronegativity?
Electronegativity:
- decreases down the group because an extra shell is added
- increases across the period because there are more protons
What is the period trend for electron affinity?
Electron Affinity:
- generally decreases down the group because an extra shell is added
- generally increases across the period because there are more protons
What is the general trend for melting point?
Melting Point:
- For Alkali metals the melting point decreases down the group
- For Halogens melting point increase down the group
- Across periods 2 and 3 melting point increases from group 1 to 4 and generally decreases from group 4 to 0
What is the first type of reaction?
2(Alkali metal) + 2H20 -> 2(Alkali metal ion) + 2OH^- + H2
What is the second type of reaction?
2(Alkali metal) + Cl2 or Br2 -> 2(Alkali metal)Cl or Br
What is the third type of reaction?
(greater electronegativity halogen)2 + 2(lower electronegativity halide ion) -> 2(greater electrnegativity halide ion) + (lower electronegativity halogen)2
2(greater electronegativity halide ion) + (lower electronegativity halogen)2 -> No reaction
What is the fourth type of reaction?
Metal oxide + Water -> metal hydroxides
What is the fifth type of reaction?
non-metal oxide + water -> acidic oxide
