Chem Periodic Table

Medeleev

Credited with the creation of the periodic table

Henry Moseley

discovered the periodic law: properties of elements are functions of their atomic numbers

Modern Periodic Table

elements are arranged in increasing atomic number

Periods

horizontal rows (tells us the number of energy levels and the valence level)

Groups

vertical columns

Luster

shine; reflects light 

Conductivity

transfers heat and electrons

Malleability

ability to be shaped into sheets

Ductility

ability to be drawn into wire 

Hardness

a measure of the relative resistance of an element to scratching or bending (small hardness = brittle)

Solubility

the ability of an element to dissolove

Metals 

• solid at room temp

• malleable

• ductile

• have luster

• conduct heat and electricity

• lose electrons

• form positive ions with smaller radii

• low ionization energy and electronegativity

• M. E. L. P. S: Metals Electrons Lost become Positive Smaller 

Group 1

Alkali Metals

Group 2 

Alkaline Earth Metals 

Nonmetals

• Gases: H, N, O, F, Cl, Group 18

• Liquid: Br

• Solids: C, P, S, As, Se and I

• Not malleable or ductile

• Brittle in the solid phase

• Lackluster

• Poor conductors

• High ionization energy and electronegativity

• Gain electrons

• Form negative ions with larger radii

Transition Metals

• Groups 3-11

• Hard solids

• High melting points

• Hg: only liquid metal

• Multiple oxidation states

• Less active than groups 1 &2

• Form ions that have color

Metalloids

“Biggie smalls and Tupac got Shot”

• B, Si, As, Te, Ge, Sb

• Found on the staircase

• Have both metal and nonmetal properties 

Halogens

• Group 17

• Highly reactive

• All three phases of matter

Noble Gases

• Group 18

• Unreactive: does NOT react with other elements. WILL NOT undergo chemical reaction

• Stable outer electron configuration

Allotrope

elements that exist in different forms - different crystal/molecular structures and different properties 

Atomic Radius

the distance from the center of the atom to the outer energy level

ions (elements with charges can have a different radius)

+ions

e- were lost —> radius is smaller

-ion

e- were gained —> radius is lost

Metallic Character

how much an element behaves like a metal

First ionization energy

the amount of energy needed to remove the last electron in an element

Electronegativity

measures the ability to attract electrons when bonding

The higher the number, the more electrons it attracts

highest = flourine (F)

lowest = francium (Fr), Cesium (Cs)

Nuclear charge

Charge in the nucleus - increases as the atomic number increases

Nuclear shielding

The outermost electrons in an atom are isolated from the nucleus by the inner elections

Nonmetallic character

How much an element behaves like a nonmetal

Metallic character trend

• decreases across a period

• Increases down a group

• Atomic radius trend

• Decreases across a period

• Increases down a group

First ionization energy trend

• Increases across a period

• Decreases down a group

Electronegativity trend

-increases across a period

• Decreases down a group

Nonmetallic character trend

- increases across a period

- decreases down a group

Melting point trend

• Group 1: decreases down a group

• Group 17: increases down a group

Lewis dot diagrams

A diagram using the chemical symbol and valence electrons of each element

Valence electrons

Electrons in the outermost shell / principal energy level /orbit

How can valence electrons be found?

1)group number:

All elements in the same group have the some number of valence electrons

2) Electron configuration:

• the last number in the electron configuration is the number of valence electrons

How to draw Lewis dot structure?

Determine the number of valence electrons and draw dots around the element symbol

Monatomic

1) Cations

• form from metals

• Lose all valence electrons

• Have a positive charge

• Each electron lost = +1 charge

• Charge must be labeled outside brackets

Anions

1) Anions

• form from nonmetals

• Gain valence electrons so shell is full

• Have a negative charge

• Charge must be labeled outside brackets