| Chem 1 H | Chapter 5 Review

atomic radius

size of atom, ½ distance between nuclei of two identical atoms bonded together.

first ionization energy

energy required to remove the highest energy e- from an atom.

second ionization energy

energy required to remove the second highest energy e- from an atom.

electron affinity

amount of energy change when adding an electron to an atom.

effective nuclear charge

actual magnitude of the positive charge experienced by an electron.

shielding

an electron in a multi-electron atom is partially shielded from the positive charge of the nucleus by other electrons in the atoms.

metalloid

some properties of metals and non-metals, semiconductors, “staircase” elements.

noble gases

very nonreactive (stable), don’t react with other elements.

lanthanide elements

4f row, “Rare” earth element, super magnets, cell phone technology.

valence electrons

electrons in the outermost shell of an atom.

periodic law

physical/chemical properties of elements are periodic functions of their atomic numbers.

(group 1)

metals Li, Na,K, Rb, Cs ,F

(group 2)

alkaline earth metals Be, Mg, Ca , Sr, Ba, Ra

(group 17)

halogens F, Cl, Br, I, At, Ts

(group 18)

noble gases He, Ne, Ar, Kr, Xe, Rn, Og

(groups 3-12)

transition metals

what’s the general trend in atomic radius across a period?

decrease

what’s the general trend for atomic radius when going down a group?

increase

what is the general trend for first ionization energy when going across a period?

increase

what is the general trend for first ionization energy when going down a group?

decrease

Mendeleev’s periodic table

organized the elements by atomic mass

Mosley’s periodic table

organized by the increasing atomic number

An electron is removed from an atom. What can be said about the magnitude of the ionization energy needed to remove the second electron?

It will be higher than the energy needed to remove the first electron.

A distinctive property for Alkali metals

soft metals, solids at room temp, highly reactive.

a distinctive property for noble gases

very non-reactive

a distinctive property for alkaline earth metals (compare to alkali metals)

soft but not as soft as group 1, reactive, but not as reactive as group 1

a distinctive property for halogens

all nonmetals, highly reactive