Peridoic Table - Chem - Quarter 3
Mendeleev and Meyer recognized predictable patterns in elements as atomic weight increased
Moseley developed atomic numbers
Properties of the atom depend on electron configuration and how the attraction between electrons and the nucleus
Electron- electron repulsion-- same charge
Cancel some of the electron nucleus attraction
More electrons= more repulsion= less attraction between nucleus and electron
Effective nuclear charge- net attraction
Less than the actual nuclear charge
increases right to left across a periodic table
Number of core electrons stays the same; the number of protons increases
increases slightly as we go down a column
bonding atomic radius: shortest distance between the two nuclei during an atomic collision divided by 2
bonding radius< non bonding radius
Atomic radius increases as you go down a column
Increasing n (energy levels) therefore greater probability of electrons being farther from the nucleus
Atomic radius decreases left to right
Effective nuclear charge decreases (less shielding ) and therefore increasing atomic radius
Cations are smaller than parent atoms
electron - electron repulsion is reduced
Anions are greater than parent atoms
electrons are added therefore electron- electron repulsion is increased, increasing radius
Isoelectronic series have the same number of electrons
When listed in increasing atomic number, nuclear charge increases ; electron number stays the same, but protons increase; stronger attraction of electrons to the nucleus; ionic radius decreases.
Ionization energy is the minimum energy needed to remove an electron from the ground state of an atom
Greater ionization energy = more difficulty removing electrons
first ionization energy is the smallest and increases with each successive ionization
Sharp increase in the ionization energy occurs when inner shell is removed
Always positive- energy must be absorbed to remove electrons
Ionization energy increases as we move across a period
Increase in effective nuclear charge and decrease in atomic radius
Ionization energy decreases are we move down a period
atomic radius increases
Electron affinity is the energy change that occurs when an electron is added to a gaseous atom
Energy is released--- answer is in negatives
Greater attraction between atom and added electron the more negative the answer
Energy change when atom gains and electron
Metals:
Low ionization energy
Loose electrons
Non Metals:
Gain electrons
Metalloids: in between the two
Group 1A-- alkali metals
Low densities and melting points
Increasing atomic radius, decreasing ionization energy
Very reactive
Group 2A -- alkaline earth metals
Denser, higher melting points
Less reactive
Hydrogen is the most reactive
Oxygen is polar
7A is halogens
8A is noble gases-- not reactive
High first ioniization energy
Mendeleev and Meyer recognized predictable patterns in elements as atomic weight increased
Moseley developed atomic numbers
Properties of the atom depend on electron configuration and how the attraction between electrons and the nucleus
Electron- electron repulsion-- same charge
Cancel some of the electron nucleus attraction
More electrons= more repulsion= less attraction between nucleus and electron
Effective nuclear charge- net attraction
Less than the actual nuclear charge
increases right to left across a periodic table
Number of core electrons stays the same; the number of protons increases
increases slightly as we go down a column
bonding atomic radius: shortest distance between the two nuclei during an atomic collision divided by 2
bonding radius< non bonding radius
Atomic radius increases as you go down a column
Increasing n (energy levels) therefore greater probability of electrons being farther from the nucleus
Atomic radius decreases left to right
Effective nuclear charge decreases (less shielding ) and therefore increasing atomic radius
Cations are smaller than parent atoms
electron - electron repulsion is reduced
Anions are greater than parent atoms
electrons are added therefore electron- electron repulsion is increased, increasing radius
Isoelectronic series have the same number of electrons
When listed in increasing atomic number, nuclear charge increases ; electron number stays the same, but protons increase; stronger attraction of electrons to the nucleus; ionic radius decreases.
Ionization energy is the minimum energy needed to remove an electron from the ground state of an atom
Greater ionization energy = more difficulty removing electrons
first ionization energy is the smallest and increases with each successive ionization
Sharp increase in the ionization energy occurs when inner shell is removed
Always positive- energy must be absorbed to remove electrons
Ionization energy increases as we move across a period
Increase in effective nuclear charge and decrease in atomic radius
Ionization energy decreases are we move down a period
atomic radius increases
Electron affinity is the energy change that occurs when an electron is added to a gaseous atom
Energy is released--- answer is in negatives
Greater attraction between atom and added electron the more negative the answer
Energy change when atom gains and electron
Metals:
Low ionization energy
Loose electrons
Non Metals:
Gain electrons
Metalloids: in between the two
Group 1A-- alkali metals
Low densities and melting points
Increasing atomic radius, decreasing ionization energy
Very reactive
Group 2A -- alkaline earth metals
Denser, higher melting points
Less reactive
Hydrogen is the most reactive
Oxygen is polar
7A is halogens
8A is noble gases-- not reactive
High first ioniization energy
