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ionization energy

a measure of the ease with which an electron can be removed from a gaseous atom or ion (sometimes called ionization potential). - the energy required to remove one outermost electron from a gaseous atom. Second ionization energy - the additional amount of energy needed to remove an outermost electron from the gaseous +1 ion.

Periodic Table of Elements

a table of the elements, arranged by atomic number, that shows the patterns in their properties; based on the periodic law

The p - Block Elements: Groups 13 - 18 -Contain metals and nonmetals (metalloids)

along zigzag line, have characteristics of both metals and nonmetals (many are good conductors but are brittle). The metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium.

periodic

occurs at regular or at least generally predictable intervals

Periodic law

physical and chemical properties of the elements are periodic functions of their atomic numbers

Lanthanides

shiny reactive metals

Group 18 - Noble gases - unreactive

unreactive. 8 electrons in outermost s and p energy levels - all are gases The s and p blocks are called the main group or representative elements!

Actinides

unstable and radioactive

Electronegativity

- the tendency of an atom to attract electrons to itself when it is chemically combined (bonded) to another element.

Group 17 - Halogens - most reactive nonmetals

-7 electrons in outermost (s and p) energy levels (that is why so reactive - only need one electron to have 8) -called the salt formers (they react vigorously with metals to form salts) A salt is a metal and a nonmetal bonded together. -most are gases most reactive non metals

The d-Block Elements: Groups 3-12 -are all metals with metallic properties (malleability, luster, good conductors, etc...); are referred to as the Transition Metals

-Harder and denser than alkali or alkaline -Less reactive than alkali or alkaline -For the most part their outermost electrons are in a d sublevel -Exceptions to the electron configuration are found in these groups (Ex: Ni, Pd, Pt)

periodic trend

The size of ions decreases as you move across a period because you have more protons pulling on the same number of energy levels.

Atomic Number

(Number of protons)

Atomic mass

(Rounded to a whole number, equals the number of protons and neutrons)

Element Symbol

(Written with a capital letter or a capital followed by a lower case if two letters

Group 2: Alkaline earth metals

-less reactive than Alkali, but still react in water to produce an alkaline solution -never found free in nature -harder, denser, stronger than alkali - ns2 (ending of all electron configurations for this group), because they have 2 electrons in the s sublevel, this makes them a little less reactive then the Alkali metals in group 1

alkali metals

-soft silvery metals -most reactive of all metals, never found free in nature -reacts with water to form alkaline or basic solutions - store under kerosene -whenever you mix Li, Na, K, Rb, Cs, or Fr with water it will explode and produce an alkaline solution -ns1 (ending of all electron configurations for this

metals, non-metals , mettaloids

3 classes of metals?

Element

A pure substance made up of one kind of atom that cannot be broken down into simpler substances by physical or chemical means 90 occur naturally on earth 25 were synthesized (made) by scientists

metalloids

Border the zigzag line/staircase on the periodic table Chemical Properties Most atoms have ½ (≈) complete set of electrons in outer level Physical Properties have properties of both metals and non-metals

Alkali Metals Alkaline Earth Metals Transition Metals Boron Group Carbon Group Nitrogen Group Oxygen Group Halogens Noble Gases Alkali Metals Alkaline Earth Metals Transition Metals Boron Group Carbon Group Nitrogen Group Oxygen Group Halogens Noble Gases

Group (Family) Names

1-18

Groups: vertical columns

Henry Moseley

In 1914, his work led to a revision of the periodic table by rearranging the elements by their atomic numbers He concluded that the number of protons in an atom is its atomic number

Dmitri Mendeleev

In the 1860's he devised a periodic table where the elements were ordered by their atomic masses He did this by grouping elements together according to their similarities

metals

Location Found on the left of the zigzag line/staircase on the periodic table (exception → Hydrogen) Chemical Properties Have few electrons in their outer energy level, thus lose electrons easily Physical Properties ductile, good conductors, malleable, shiny, most are solid @ room temperature

non-metals

Most found to the right of the zigzag line/staircase on the periodic table Chemical Properties Most have almost full outer energy levels, thus they tend to gain electrons; some have completely full outer level Physical Properties not ductile or malleable, not shiny, poor conductors, most are solid, but some are gas at room temperature

(# 1-7)

Periods: horizontal rows

atomic radii

The size of an atomic radius cannot be measured exactly because it does not have a sharply defined boundary. However the atomic radius can be thought of as ½ the distance between the nuclei of identical atoms joined in a molecule

Electron Affinity

the energy change that accompanies the addition of an electron to a gaseous atom. The desire of an atom to have another electron. Chlorine for example would like to have another electron and therefore has a very high electron affinity.

Periodicity

the similarities of the elements in the same group is explained by the arrangement of the electrons around the nucleus.

group trend

the size of the ions decrease as you move up a group (or increase as you move down a group) because the number of energy levels increases.