Unit 4 Part II Notes (Metallic Bonding & Traits)

Some molar mass notes & empirical/molecular formula

Metals are ___ (Five answers)

Malleable (pounded into sheets)

Ductile (drawn into wires)

Conductors (Of both heat and electricity)

Lustrous (Surface is reflective/shiny)

Element or Mixtures (Alloys)

A mixture of metals is not ___

Is not a compound (because approximation)

It is a homeogenous mixture

Metalic properties result from ___

the arrangement of particles on the atomic level.

Cations and Fixed Positive Ions have what structure?

Cations & Fixed Positive Ions are in a crystal lattice

Valence elctrons are ___

Delocalized or “Free moving” - called a “Sea of Electrons”. Electrons are attracted to more than one cation at a time.

Metal/Cation Structure is held together by ___

Electrostatic attraction (Only for metals/cations)

Malleability and Ductility result from ___ (2 answers)

Fixed Cations in a sea of electrons.

Sufficient presure can force cations in a lattice to slide past each other.

Also:

Metal cation crystal lattice is not rigid like ionic compound lattice.

Luster results from ___

Photos of light not penetrating very far into the surface of a metal and are typically reflected or bounced off the metallic surface (metals typically have a shiny metallic luster).

All eletrical conductivity is ___

is based on moving charges.

Metals always have moving charges (sea of electrons) that can be induced (forced) to move in a specific direction with an applied charge - (s) or (I)

Ionic compounds have __ electrons __

Ionic compounds have transferred electrons locked in place with ions in rigid crystal lattice.

Ionic compounds do ___ (conductivity)

Ionic Compounds do not conduct in solid(s) form

Ionic compounds in ___ or __ (conductivity)

ionic compounds in water or melted (state) break bonds so it can conduct electricity

Ions are now seperate moving charges

(most) covalent compounds have ___ (conductivity)

no charges and don’t conduct in any state.

Heat is a measure of ___

Temeperature is a measure of ___

Heat is a measure of kinetic energy

Temperature is average kinetic energy

Metals conduct heat because ___

Electrons are delocalized

it takes very little energy to make them move faster, increasing the temperature of the metal

C_p of metals is ___

C_p of metals is low

C_p = specific heat capacity

The amount of heat required to change the temperature of 1 gram of a substance by 1 degree Celsius

Covalent compounds require more __ (conducting heat)

Covalent compounds require more energy to make their particles move faster and raise their temperature, making them insulators for heat. Their electrons are localized.

C_p of nonmentals is ___

C_p of nonmetals is high.

Trends of melting points in metals include __ (6 answers)

Melting point increases across periodic table

metallic bond strength increases with the number of valence electrons and charge of cations (across table)

more valence e^- and cation charge = stronger metallic bond

MP increases down the periodic table

Metallic bond strength decreases as cation radius increases (down table)

Greater cation distance from valence e^- = weaker metallic bond

Summar of all 3 types of bonds (not a flashcard)

Summar of all 3 types of bonds (not a flashcard)

1 mole = ___

6.022 × 10²³

^{Avogrado number}

^{Their is exactly 1 mole of atoms in the atomic mass of an element when that mass is expressed in grams.}

Molecular formula is ___

Empirical formula is ___

the actual number of atoms of each element in a compound

the simplest ratio of the elements in a compound

Steps to find Empirical Formula =

1.Find the number of moles of each element.

2. Identify the smallest number of moles.Then, divide all the moles by that smallest number.

3. Round up or down to get whole numbers for each element. 

• If you get something like .3, then multiply all your values by 3 to get the whole numbers.

• If you get something like .5, then multiply all your values by 2 to get the whole numbers.

Steps to find molecular formual =

• Knowing the molecular mass and the empirical formula allows you to find the molecular formula

• Ratio of molecular:

  • Empirical formulas is equal to the ratio of their masses

Hydrates are __

• A hydrate is a compound that has a specific number of water molecules bound to its atoms.  

• These water molecules become part of the crystal lattice & are called water of hydration.

Anhydrous Salt:

• Used as drying agents to absorb water 

• Desiccants

• We can use the same percent composition formula to figure out % of water in a hydrate.