Chemical Bonding: Ionic & Covalent

Chemical Bonding: Ionic & Convalent

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What we will cover today

• Definition of a chemical bond

• Difference between ionic and covalent bonds

• How to write chemical formula

What is a chemical bond?

What is a chemical bond?

• atoms are rarely found on their own

• bonding occurs when valence shell electrons interact together

• they occur because atoms want to be STABLE with a FULL outer shell

What can we see about metals and non-metals when we look at these charges?

What can we see about metals and non-metals when we look at these charges?

​Metals lose electrons

​Non-metals gain electrons

Multiple Choice

What type of bonding does this picture show?

• Ionic

• Covalent

Multiple Choice

What type of bonding does this picture show?

• Ionic

• Covalent

Ionic Bonding

• complete transfer of electrons

• metal + non-metal

• very strong bonds

• 'balancing out' of the charges between the atoms

How to write ionic formula:

• 1. Determine the ionic charge of the metal and non-metal atoms

• 2. Drop and swap the charges

• 3. Check the charges are balanced!

Covalent Bonding

• sharing of electrons

  • they both need to gain electrons ​

• between non-metal + non-metal

• again, it's all about forming a full valence shell - a full octet

Multiple Choice

Which of these element pairs would bond covalently?

• Fr and K

• Sc and O

• F and Cl

• He and Pt

How to write a covalent formula:

• 1. Determine how many electrons each atom needs to be considered stable

• 2. ​Determine how each of the atoms will share the electrons

• 3. Can draw the ​electron-dot structure

• 4. Write formula ​

Drawing a Lewis dot diagram: Covalent

• 1. Draw out the number of electrons on the valence shell for each atom

• 2. Determine how many electrons the atoms need to make a full outer shell

• 3. Re-draw them as bonded (this is a double bond)

Drawing a Lewis dot diagram: Ionic

• 1. Draw out the number of electrons on the valence shell for each atom

• 2. Determine how many electrons the atoms need to make a full outer shell

• 3. Re-draw them with transferred electrons/bonded

• 4. Input charges and brackets ​

Naming compounds:

• ionic = name of the metal + name of the non-metal with suffix -ide

• covalent = number of atoms prefix+element name + number of atoms prefix+element with -ide root

Multiple Choice

The chemical bond between a metal and a non-metal will be a _____ bond.

• metal

• ionic

• covalent

• polar

Multiple Choice

What is the formula for diphosphorus pentoxide?

• P₂O₅

• PO₅

• P₅O₂

• P₂O₆

Multiple Choice

What is the correct name for NO?

• Mononitrogen Monoxide
• Nitrogen Monoxide
• Mononitrogen Dioxide
• Nitrogen Oxide

Multiple Choice

Which formula is for phosphorus trichloride?

• KCl₃

• PCl₃

• K₃Cl

• P₃Cl

Multiple Choice

Lead Chloride is an ionic compound, made up from Pb²⁺ ions and Cl^- ions. Which is the correct formula for this compound?

• PbCl₃

• PbCl

• PbCl₄

• PbCl₂

Multiple Choice

Magnesium Hydroxide is an ionic compound made up from Mg²⁺ and OH^- ions. Which is its correct formula?

• MgOH

• MgOH₂

• Mg(OH)₂

• MgO

​Transition Metals and Variable Charges:

​You might see in some questions that there are roman numerals​ in brackets after an element symbol OR there is a transition metal of which you are unsure of the charge. There are two rules about this:

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1. If there is a roman numeral, this is the ionic charge of the atom

2. If there is no roman numeral, you assume the ionic charge i​s 2+

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Ti(III) = Ti³⁺

Mn = ​Mn²⁺

Polyatomic ions:

The same as normal ionic bonding, except we must keep the polyatomic ion together. So we use brackets to do so.

Open Ended

What questions do you have about this content? I will answer them quickly now, or will do so next lesson :)