Periodic Table Trends and Bonding (Unit 1 Grade 11 Chemistry)

Periodic Table Trends and Bonding (Unit 1)

Grade 10 Knowledge

• Carbonate

  • ​​​​​​CO₃^2-

• Hydroxide

  • OH-

• Phosphate 

  • PO₄^3-

• Fluorate

  • FO₃^-

• Bromate

  • BrO₃^-

• Ammonium

  • NH₄⁺

• Permanganate

  • MnO₄^2-

• Nitrate

  • NO₃^-

• Sulfate

  • SO₄^2-

• Chlorate

  • ClO₃^-

Prefixes for Polynomial 

• Per_____ic acid- 

• X+ 1

• ________ic acid

• X

• _______ous acid

• X -1

• Hypo____ite acid

• X - 2

• ________ic

• HOFBrINCl

• mnemonic device used in Chemistry to remember the diatomic molecules, which are molecules consisting of two atoms

• Hydrogen, Oxygen , Fluoride, Bromine, Iodine, Nitride, Chloride

• Atomic Radii

• Atomic Radii is the size of an atom, similar to the word “Radius”, It’s chemistry’s unit of measurement to find the radius of an atom.

• Atomic Radii Trend

  • On the Periodic Table, there’s a trend that shows that any element that progresses furthest to the bottom left of the periodic table will have a larger atomic radius than those on the top right, being the largest. The Alkali Metals are a perfect example as they gain an additional energy shell than the previous element and have 1 electron on their outer ring, leaving with the results of a lower force of attraction.

 This rule isn’t applicable to every SINGLE element but for the most part, it is accurate. 

• Effective Nuclear Charge

  • Known as “Zeff” or just “Z”, It’s the positive charge of pulling electrons towards the nucleus. To not confuse you, it is completely different from its actual nuclear charge as it’s based on the attraction close to the positively charged nucleus (relying on the amount of protons existing) rather than the amount of electrons it’s attempting to attract to satisfy its valence. 

To simplify, It’s determined by the outer shell amount of electrons, representing itself as “Zeff.” To discover this we must set an example, Carbon (C) will be our example. Carbon has a charge of 4+ or - but to answer its effective nuclear charge, we must subtract its inner rings worth of electrons to find our Z. Formula is built off as “Zeff = #protons - #inner electrons.” Giving us the answer that Carbon’s Zeff is 4.

• Ionization Energy

  • It’s the measurement to see the amount of energy required to remove an electron from an isolated atom to acquire a negative or positive charge. 

• Ionization Energy shown on the Periodic Table

  • On the Periodic Table, There’s a trend that is shown that any element that is closest to the top right of the periodic table will have the highest amount of ionization energy. Example would be the Noble gases as they are the only elements with a complete valence shell, hence why you almost never see them mixed with other elements as it requires a lot of energy to remove a single electron from its shell. 

This rule is not implemented to every SINGLE element but overall accurate to be a trend.

• Electron Affinity

  • A measurement of the attraction between the incoming electron and nucleus. It’s basically the opposite of ionization energy on the periodic table as instead of measuring the amount of energy change after gaining an electron.

• Electron affinity Trend/Ionization Energy shown on the Periodic Table

  • On the Periodic Table, There’s a trend that is shown that any element that is closest to the top right of the periodic table will have the highest amount of ionization energy/Electron Affinity. Example would be the Noble gases as they are the only elements with a complete valence shell, hence why you almost never see them mixed with other elements as it requires a lot of energy to remove/add a single electron from its shell.

This rule is not implemented to every SINGLE element but overall accurate enough to be a trend.

• Reactivity (Same trend as Radii)

  • Metals react by losing electrons and the lower the attraction for outer electrons, the greater reactivity.

  • Non metals react by gaining electrons

  • The greater the attraction for outer electrons, the greater the reactivity. 

• What is a bond?

  • It’s the association of atoms or ions to form molecules, crystals or other structures.

• What is a dipole?

  • A molecule that has both positive and negative charges, commonly seen when a bond is polar.

  • Inbalance of atoms that have positive or negative charges. (May be more positive charges than negative or more negative charges than positive

• What is Electronegativity? (EN)

  • The tendency of an atom that is in a molecule to attract a shared pair of electrons towards itself.

• What is a polar bond?

  • When two different elements form a bond by sharing electrons and there’s an unequal balance of electrons, most of the time, there’s lone pairs.

  • Comes from the differences between electronegatvitiy if the EN is higher than 0.5 but less than 2, confirming the bond to be polar.

  • Higher electronegativity results in a greater attraction for electrons

• What is a nonpolar bond

  • A balanced amount of electrons are distributed to all atoms within the molecule, sharing electrons equally and creating no positive or negative poles, no lone pairs.

  • Comes from the differences between the electronegativity if the EN is lower than 0.5

• What is a Partial Charge?

  • Non-integer or determined charge value when measured in “elementary” charge units.

  • Represented in the symbol Delta

• Ionic Bonds

  • It’s the process of 2 or more atoms transferring its electrons to another atom in order to complete their desired valence shell amount. This bond only happens between a metal and non-metal atom. 

  • Note that an electron transfer will cause a negative charge (Known as anion, an ion that is negatively charged) or positive charge (known as a cation, an ion that is positively charged).

  • All electrons lost by the metal are gained by the non metal

  • If EN is higher than 2 then it is an ionic bond

• Properties of ionic substances/compounds

  • Crystal lattice when solid at room temperature

  • High melting/ boiling points

  • Hard but very brittle in water

• Covalent bonding

  • A bond that happens between a non metal and nonmetal. Main difference from ionic bonds is that they share electrons rather than transfer their electrons creating a new type of compound which is called “Covalent Compound.” 

  • No ions are formed from the creation of the compounds.

• Formula for drawing Lewis Dot Diagram 

  • # of atoms • electron amount +... = total number of electrons

• Properties of non-metal substances/compounds

  • Form molecules that can turn into any state of matter (Solids, liquids, gasses)

  • Low melting/ boiling points

• Multiple Bonds Resonance structures

If you’re not certain where the bonds need to go so you show all possible solutions.

• Expanded  Valances

Octet rule allows a max of 4 bonds but some allow 8, only for those with an atomic number greater than 10.

VSEPR Geometry

• What is VSEPR?

• VSEPR stands for valence shell electron pair repulsion and it presents us with the idea that electron pairs repel each other whether or not they are in bond pairs or in lone pairs.

• Formula for VSEPER is AB#E#
  A represents Central Atom

B represents Bonding Electron Pairs

E  represents non bonding lone electron pairs 

# represents the amount of Bonding electrons there are or lone pairs.

• What are the three dimensional representations in VSEPR

• Lines represent it’s across 2 dimensionally 

• Triangle represents it’s towards you

• Dotted Triangle represents it’s behind the central atom

• VSEPR Diagrams

• There are 5 different types of Diagrams you must remember and their formulas.

1. Linear Diagram 

• A straight line

• Formula = AB2E0

2.  Bent Angular Diagram 

• Bent shape

• Formula = AX2E0 or AX2E2

3. Trigonal Planar 

• Triangle Shape 

•  Formula = AX3E0

4. Trigonal Pyramidal 

• Will have 4 points, resembling a pyramid.

• Formula = AX3E1

5. Tetrahedral 

•  Similar to a trigonal pyramidal but no lone pairs and exact same shape. 

• Formula = AX4E0  

Intermolecular and Intramolecular Forces 

• Intramolecular Forces

• The force of electrostatic attraction inside a molecule

• Bonds that hold the atoms together to form a molecule, including Ionic Bonds, Polar covalent, non polar covalent.

• Extremely strong and in order to be broken, must have chemical means.

• London Dispersion Forces (Apart of Intramolecular Forces)

• These forces exist between all molecules 

• Weakest type of Intramolecular force

• Because electrons move around, some spaces will be asymmetrical 

• The greater # of electrons and protons, the greater the force.

• Dominant Force in non polar molecules.

• Dipole - Dipole Interactions 

• Occur between polar molecules that already have dipoles.

• Oppositely charged ends

• Unequal distribution of charges on the molecule.

• Hydrogen Bonds (Apart of Dipole Dipole)

• Specific type of Dipole Force. 

• Occurs between hydrogen atoms and high electronegativity valued atoms (F, O, N) within a molecule.

• Ionic Forces

• Can be both inter or Intra forces.

• Strongest overall force.

• Intermolecular Forces

• Forces of attraction between two molecules

• Much weaker than Intramolecular forces 

• Due to how fragile this force is compared to Intramolecular Force, Physical changes can break or weaken these forces.

• Predicting boiling point using the strength of intermolecular forces 

• The more polar molecule present, the stronger dipole-dipole and higher boiling point.

• You can determine the boiling point by discovering the EN 

• Higher the EN, the higher boiling point.