S2 Bonding and Structure

What is an ion?

Charged particle formed from losing or gaining electrons

Cation

positive ion formed when losing electrons

Anion

Negative ion formed when gaining electrons

What ions do groups 1-3 typically form?

cations

What ions do groups 5-7 usually form?

anions hat W

What ions do groups 4-8 typically form?

Do not tend to form ionic bonds

how do transition elements ionically bond?

They lose different amounts of electrons from their sub levels

How to name ionic compounds

Cation then anion, anion name has -ide added to the end

How does position on Periodic Table indicate ionic character?

Metals on the right lose electrons, non-metals gain electrons. Highest tendency to form ionic compounds occurs with elements in bottom left with elements on top right

How does electronegativity indicate ionic character?

differences greater than 1.8 show ionic bonds

What is ionic bonding?

electrostatic force between positive and negative ions, acting in all directions

What shapes do ionic compounds form?

form 3d crystalline structures (ionic lattices)

What does a coordination number indicate?

expresses no. of ions surrounding a given ion in lattice

What is lattice enthalpy?

measure of the strength of the forces between the ions in an ionic solid

Lattice Enthalpy trends

smaller the ion and greater the charge, the higher the lattice enthalpy

Factors of Lattice Structure

The charge on the ions and the radius of the ions

Is Lattice Enthalpy exo or endothermic?

Endothermic due to energy being absorbed to form ions

Physical Properties of ionic compounds

high melting/boiling points, low volatility, liquid/gas conduct electricity, solids don’t, compounds are highly brittle/shatter

What is Covalent Bonding?

when two non-metals react together in order to achieve stable electron configuration

How to tell which atom is the central atom

the atom with the lowest subscript, or the least electronegative atom

What are coordinate covalent bonds?

when both electrons in the bond originate from the same atom

Relationship between bond length and strength

inverse relationship, shorter bonds are stronger