ch 171 - chapter 3 (electronic structure & the periodic law)

Atomic orbital

a region of space in which there is a high probability of finding an electron. a three-dimensional region around the nucleus of an atom that describes an electron's probable location

Distinguishing electron

the last electron added to the electron configuration for an element when electron subshells are filled in order of increasing energy.

Electronic configurations

the ways in which electrons are arranged in various orbitals around the nuclei of atoms

First ionization energy

the energy required to remove the first electron from an atom.

Group/family on periodic table

a vertical column of elements having the same valence electron configuration and showing similar properties (GC)

Hund's rule (long explanation)

electrons will fill degenerate orbitals (orbitals with the same energy level) singly as much as possible. If multiple orbitals have the same energy, each orbital will get only one electron geode any orbital gets a second one. Also, the single-occupied orbitals will have electrons with parallels spins, which maximizes the total spin of the electrons (which is more stable due to e- repulsion being minimized).

Hund's rule (short explanation)

Electrons will not pair with other electron in an orbital, if an empty orbital of the same energy is available

inner transition elements

lanthanides and actinides (F BLOCK)

Metals

Elements that are good conductors of electric current and heat.

Metalloids

Elements that have properties of both metals and nonmetals.

Noble gas configuration

an outer main energy level fully occupied, in most cases, by eight electrons

Nonmetals

Elements that are poor conductors of heat and electric current.

Pauli exclusion principle

An atomic orbital may describe at most two electrons, each with opposite spin direction. electrons behave as if they spin on an axis, and only electrons spinning in opposite directions (↑↓) can occupy the same orbital.

Periodic law

the law that states that the repeating chemical and physical properties of elements change periodically with the atomic numbers of the elements

Period of the periodic table

Horizontal (—) rows on the periodic table

Representative element

elements from groups 1, 2, and 13-18 in the modern periodic table, possessing a wide range of chemical and physical properties

Shell

the energy level occupied by an electron determined by the distance from the nucleus. Represented by numbers 1,2 & 3.

Subshell

A subdivision of an energy level in an atom. They are divided into orbitals (s, p, d, f)

Transition element

elements in Groups 3 through 12 of the periodic table

Valence shell

The outermost energy shell of an atom, containing the valence electrons involved in the chemical reactions of that atom.

F to C

C = 5/9(F-32)

Do chemicals in the same families have similar properties?

Yes, chemicals in the same families (groups) have similar chemical properties.

When do electrons change orbits?

When they absorb or release energy.

How many electrons are in the third shell of Pb?

18. The third shell has 3s, 3p, and 3d. 3s holds 2 e-, 3p holds 6-, and 3d holds 10 e-.

Ionization energy

The amount of energy required to remove a distinguishing electron from an atom’s valence shell

Ionization energy trend

Ionization energy increases up and to the right

electron affinity

the energy change that occurs when an electron is acquired by a neutral atom

electron affinity trend

Electron affinity increases to the right and up

Atomic radius

one-half the distance between the nuclei of two atoms of the same element when the atoms are joined

atomic radius trend

increases down a group, decreases across a row/period