chem uni 3

What are Alkali Metals

The most reactive metals

What are Alkaline earth metals

Second most reactive metals

What are Noble gasses

The least reactive nonmetals, and the least reactive elements overall.

What are transition Metals

The least reactive metals.

what are halogens

 The most reactive nonmetals

What are the representative elements

Groups 1,2, and 13-18

What is atomic radius

the distance from the nucleus to the edge of its electron cloud.  It increases to the left and down on the periodic table.

The increase arrows  for Atomic Radius

The Increase arrows for Atomic Mass

Atomic Mass

 the weighted average of the sum of protons and neutrons an element’s naturally occurring isotopes.  Also, the weight of one mole of that element, in grams.  Increases to the right and down. (See picture)

Ionization energy

 the amount of energy it takes to remove an electron from an atom.  (Increases right and up.)

Electron affinity

the amount of energy an atom will give up to gain a new electron.  (Increases right and up.)

Electronegativity

the attraction an atom has for a shared electron in a chemical bond.  The atom with a stronger electronegativity will pull a shared electron closer. (Increases right and up.)

Increase arrows for all trends besides radius and mass

Nonpolar covalent bond

A bond in which the electronegativity difference is 0.4 or less

Polar covalent bond

 A bond in which the electronegativity difference is between 0.4 and 1.7

Ionic bond

 A bond in which the electronegativity difference is greater than 1.7

Isotope

An atom of an element with a different number of neutrons.  

Isotopic notation

Consists of two numbers on the left, one on top of the other, and the elements symbol on the right.  The top number is the mass number, which is the total number of neutrons plus protons.  The bottom number is the atomic number, which is the protons alone.  The name of the isotope is derived from the name of the element, followed by a dash, followed by the mass number.  (See Picture for an example of Carbon-12.)

Electronic configurations

valence electrons

elements in a group have similar properties due to these

law of octaves

this law did not work for group 2 elements

law of triads

this law revealed that the math did not work for all groups of elements, like the halogens

How do you find Atomic mass

Protons + Neutrons = Atomic Mass Number (Mass Number - Atomic number = Number of Neutrons)