| A | B |
|---|
| atomic size main group elements | atomic radii generally increase going down a group in the periodic table and decrease going across a period |
| effective nuclear charge (Z*) | in going from one element to the next across a period increases. results in an increased attraction between the nucleus and valance shell electrons, and atomic radius decreases. |
| atomic size transition metal atoms | left to right in period radii initally decrease, but sizes in middle of transition series change very little, and a small increase in size occurs at the end of the series |
| ionization energy (IE) | energy required to remove an electron from an atom in the gas phase. always positive bc supplying energy |
| Electron affinity (EA) | the energy change for a process in which an electron is acquired by the atom in the gas phase. the greater the affinity, an atom has for an electron, the lower the E of the ion will be compared to that of the atom and the free electron, and the more negative the value of EA. |
| Ion sizes | + and - ions increase in size when descending a group. when an electron is removed from an atom to form a cation the size shrinks considerably. Anions are always larger than the atoms from which they are derived |
| isoelectronic ions | have same number of electrons but different number of protons. as # protons increases in a series of isolectronic ions, the blalance between electron-proton attraction and electron-electron repulsion shifts in favor of attraction, and radius decreases |
| main group metals | generally form cations with an electron configuration equivalent to that of the preceding noble gas |
| nonmetals | generally acquire enough electrons to form an anion with the electron configuration of the next noble gas |
| Pauli Exclusion Principle | no two electrons in an atom can have the same 4 quatum numbers. so, electrons in a given orbital have opposite m_s quantum number |
| Paramagnetism | weak attraction to a magnetic filed due to unpaired electron(s) in an atom or substance. |
| diamagnetism | weak repulsion to a magnetic field. all matter has some diamagnetism, but paramagnetism can be stronger. |
