Unit 2 Chem: Matter, Atomic Structure and Periodicity

Coulombs Law:

Distance matters more than charge

Reactivity:

• Most reactive metals are the largest since best electron donors (Low IE, low Electronegativity) and larger atoms lose electrons more easily

• Most reactive nonmetals are the smallest, best electron acceptors (high IE, high Electronegativity) gain electrons more easily

Atomic Structure: How the periodic table represents+organizes elements based on atomic structure

Periodic Law: When arranged by atomic #, the elements display a regular and repeating pattern of chemical and physical properties

• Principal Energy Levels are same as the period #

• Sublevels (s, p, d, f) are clustered together

• Valence Electrons are the same in each column/group

  • The chemical behaviors of each element is determined by their valence electrons, so each group/column also similar chemical properties

• Diagonal Rule is how the periodic table is organized

Types of Atoms: State, Type, Special Groups

Metals:

• Properties:

  • lustrous(shiny)

  • ductile

  • malleable

  • good conductor

• Mostly solid at room temp (except mercury)

• Tend to lose valence electrons (USUALLY CATIONS)

Non-metals(opposite of metals):

• Properties:

  • Dull

  • Brittle

  • Insulators

Metalloids(Semi-Metals):

• Properties:

  • Shiny yet brittle

  • Semiconductors

  • Solid

  • hard

  • Ability to form metallic alloys

Alkali Metals:

• Group 1 (Hydrogen Exception cuz it’s a non-metal)

• extremely reactive metals

• 1 valence electron

Alkaline Earth Metals:

• Group 2

• Not as reactive as alkali metals

• 2 valence electrons

Halogens:

• Group 17

• Highly reactive non-metals

• Only group that has all states of matter in it

  • Solid, liquids and gases

• 7 valence electrons

Noble gases

• Group 18 excluding Oganesson

• Non-reactive Gases

  • Low or close to none electronegativity

  • Stable

  • Full shells → stable

• Full Valence Shell

Transition + Inner Transition Metals (Inner are F Block):

• Groups 3-12

• Give Colored compounds

• Electrons fill inner shells

Main Group Elements:

• Along with a few light transition metals, most abundant elements in universe + Earth

• 80% of earth’s crust

• Also known as Representative elements

States of Matter

• Liquids:

  • Bromine(Br)

  • Mercury(Hg)

• Gases

  • Noble Gases

  • Nitrogen

  • Oxygen

  • Fluorine

  • Chlorine

  • Hydrogen

Periodic Trends: Patterns that follow by groups and periods (properties+structures of the atom)

Ionization Energy: The amount of energy needed to remove a valence electron.

• Increases going across a period

  • Closer an atom is to a stable state → more it wants to holds onto its electrons

  • Radius decreases → stronger force of attraction between nucleus and protons (distance matters more (Coulombs Law))

• Decreases going down a group

  • Since the atomic radius increases it is easier to remove the valence electron (coulombs law: distance matters more than charge)

• If you remove enough electrons that you move to the next shell, the IE will experience a huge jump in value

Electronegativity: The ability of an atom to attract electrons into its valence shell

• Increases going across a period

  • Lessening atomic radius + more protons → greater pull compared to leftist elements

  • Closer an atom is to a stable state → more it wants electrons to complete tis valence shell (become stable)

• Decreases going down a group    

  • increasing atomic radius (despite increasing protons, cause distance matters more (coulombs law)) → Less attractive force to fill up valence shell

Atomic Radius: The distance between an atom’s nucleus and valence shell/electrons

• Decreases going across a period

  • Increasing # of protons but same PEL → Force of attraction increases (charge from protons) and radius becomes smaller

• Increases going down a group

  • Increasing # of electrons, so more shells

    • electrons repel each other

• Anions of an element have a larger radius, cations have a smaller radius

  • electrons repel eachother