Chemistry chapter 5 Ionic bonding and structure

5.1-5.3

Define atomic orbitals

A reigon around the nucleus where electrons could be found thatt can hold two electrons with opposite spins.

Define principle quantum number.

It is the number that describes main energy level or number of shells (period roll). Which is represented with the symbol (n).

Define energy level

Another word for the number of shells of an electron.

Define shells.

The same as energy level or a group of atomic orbitals with the same principle quantum number.

Define sub- shells.

A group of orbitals with the same type within a shell

Describe the structure of a Bohr model.

There is a positive nucleus and electrons surounding in a fixed and circular orbit.

What is the difference between orbit and orbital?

Orbital is a 3 dimentional region where there is a high probability that electrons can be found.

Orbit is a fixed and circulating path of something following the other.

What proves the Bohr model wrong and explain. (4)

• A spectrum of hydrogen shows that shells are not equally spaced like the Bohr model

• The spacing of the shells decrease as you move further away from the nucleus

• The further away an electron is from the nucleus, the weaker the electrostatic attraction

• The less pull there is it from the nucleus, the easier it is for an electron from a lower energy shell to jump to a higher one

What are the four types of orbitals and their shape and properties?

1. S orbital- Spherical shape- 1 in every principle level

2. P orbital- Dumbell shape- 3 in every principle level

3. D orbital- various shapes- 5 in every principle level

4. F orbital- various shapes- 7 in every principle level

What is the order for filling an orbital? (2)

• In an increasing energy level

• 4s gets filled before 3s does due to the overlapping sub levels and 4s has a lower energy level

What are the three rules/ principles of filling orbitals?

1. Paul’s exclusion principle- the two wlwctrons that each orbital hold must have opposite sins due to the repulsion of both negatives

2. The Aufbau principle-  The electrons wil enter the lowest available energy level 

3. Hand’s rule of Maximum multiplicity- When in orbitals of the equal energy level, electrons will try to remain unpaired (reduce repulsion)

Define electron configuration?

It is the arrangement of electrons in an atom’s shell, subshells and orbital.

What is the rule of writing electron configuration ?

It should be written in a shell/ numerical order rather than the filling order

Why do we say chromium and copper have unexpected electron configuration?

Because their 4s should be filled before 3d does but instead, 3d is filled first because a more stable lower energy level subshell is needed to be half full or completely full.

What are positive and negative ions called and do they lose or gain electrons?

positive ions= cations= losing electrons

negative ions= anions= gaining electrons

What is the order for electrons to be removed?

they are removed from the highest energy level first.

Why does a 4s sub- shell empties before 3d subshell does?

Because a filled 3d sub-shell will drop to a lower energy level, so the 4s sub- shell with a higher energy level will be emptied first.

Define ionic bonding

A strong chemical bond that is formed by the elecctrostatic attraction between oppposite charges that is formed when electrons are transfered.

What are the example of cations? (2)

• Metal ions

• ammonium ions

What are the two types of anions? (2)

• Non metals

• polyatomic ions

What does the dot -and- cross diagram shows? (3)

• The electrons on the outer shell 

• postive and negative ions that are formed

• How ions formed have the same electron configuration as the nearest noble gases

How does the loss or gain of electron affect the size compare to the original atom? (cations and anions)

loss of electron- cations- positive ions - is smaller than the the original atom as it has lost a layer of shell and the remaining electrons are pull more tightly to the nucleus.

gain of electrons- anions- negative ions- is bigger than the original atoms due to the increased replusion between electrons and a weaker pull from the nucleus (further)

Define ionizing energy and what kind of reaction it is.

Ionizing energy is the minimum amount of energy required to remove (one mole of) electrons from a(one mole of) gaseous atoms or ion.

It is an endothermic reaction.

Why does this ionizing energy increase across the period but decrease down a group? (2)

• This energy increases across the period due to the increasing number of protons, pulling the electrons in the outer shell towards the nucleus

• It decreases (less energy needed to remove electrons) down the group as the outer electron will be further away from the nucleus due to more shells being added

What is the difference between ionizing energy and electronegativity? (3)

Ionizing energy is the energy needed to remove an electron while electronegativity is the ability to attract electrons from a chemial bond.

They both increase across period and decrease down the group in the periodic table

High ionizing energy = more energy is needed to overcome the force of attraction to seperate an electron (strong hold to its own electron) = that same element also have a high electronegativity with the ability to attract other electrons (as the nucleus have a strong attraction)

Define energy affinity and whta is the kind of reaction is it?

The energy changed/ released when an electron is gained/ added to a neutral gasoeus atom.

It is an exothermic reaction.

Why does a lower energy state mean being more stable?

Because a lower energy state meaning electrons will be closer to the nucleus. The closer the electron is, the stronger the force of attraction between nucleus and electron, meaning it is harder and need more energy to move the electron- making them more stable.

Describe the kind of structure in ionic compounds.

Giant ionic lattice where oppositely charged ions are held in a 3 dimensional lattice due to electrostatic attraction.

Describe ionic compounds in terms of its melting point.

Ionic compounds have high melting points, as the strong electrostatic attraction cause a large amount of energy needed to overcome this attraction to break the lattice and seperate the ions.

Describe ionic compounds in terms of its strength.

Ionic compounds are brittle because if the layers of the lattice are dislocated by a force, the charged ions would be adjacent, causing repulsion and splits the crystal.

Describe ionic compounds in terms of its electrical conductivity.

Ionic compounds do not conduct electricity when they are in a solid state as the ions are not free to move or mobile (packed closely together). But when they are molten or dissolved in water, the ions would be able to move and carry current.

Describe ionic compounds in terms of its solubility.

Ionic compound dissolve in water as 

• Polar water is attracted to the ion compound’s surface

• When water molecules are bond to the ions due to the delta positivity(hydrogen) or negativity (oxygen), they weakens the ionic bonding

• Ionic bonds are broken as new attractions from the water outweigh the strong electrostatic attraction between the ions

• Ions are then surrounded by water molecules and break free from the lattice.

Define covalent bonding. (2)

A srong chemical bond that is consist of a shared pair of electrons with one electron given by each atom on each side. It is formed by electrostatic attraction shared electrons and nucleus.

What type of elements do covalent bonds usually form between? (2)

non- metals

polyatomic ions

What is the purpose for electrons to be shared in covalent bonds? 

To get a full outer shell/ octect that has the same electron configuration as its nearest noble gas for stability.

What is the structure in covalent bonds and how does it affect the strength of the bond? (2)

In covalent bonds, two orbitals overlap, creating a reigion of sharing electrons.

The greater the overlap, the stronger the bond

What is the name for a pair of electrons that are not shared with another atom in bond?

lone pair

What are the differences between ionic compounds and covalent compounds in terms of attractions? (4)

In ionic bonds, ions attract opposite charges in three dimensions and all directions around the ion

In covalent bonds, the attraction is only between the shared pair of electrons and the positive nucleus.

Covalent bon attraction is localised- limited in a particular place

When the force of attraction between electrons and nucleus is too big and can’t be overcomed, convalent bonds occurs instaed of ionic bonds because electrons cannot be removed so they share with each other to form a full outer shell.

Define dative covalent bonding.

Another word for corrdinate bond. It is a strong covalent bond where both shared electrons come from the same atom/ specie.  

What are the names for the atom that gives all of the sharing electrons? (2)

• lone pair donar

• lewis base

What are the names for the atom that receives all of the sharing electrons? (2)

• lone pair acceptor

• lewis acid

What are the two main conditions for dative covalent bonds to happen?

• Donar species have loner paris in the outer shell

• Acceptor speciess would need to fill its outer shell.

What represents dative covalent bonds in a display formula?

an arrow

Define average bond enthalpy.

 a measurement of the bond strength.

What are the physical properties of the covalent bonds? (3)

1. Electrical conductivity- Not conductive- as there are no mobile ions

2. Solubility- some dissolve in non polar solvents and some dissolve in polar ones

3. Boiling point- low as only weak intermolecular bonds are needed to be broken.

Why so some have higher boiling points than others? (1)

Due to the size of the molecules leading to stronger intermolecular force in between needed to be broken down to change state.

Define metallic bonds.

It is the strong chemiscal bond formed by electrostatic attraction between a lattice of positive metal ions and a sea of delocalized electrons.

Describe the structure inside metals and metallic bonds. (2)

Metals have delocalised electrons are formed in the outer shell as metals need to lose electrons to gain a full outer shell to have the same electron configuration to the nearest noble gas.

These free electrons join up to form a mobile cloud that traps or prevent the positive ions to fly apart due to their own repulsion.

Describe metallic bonds strengths in terms of the amount of the electrons and size of positive ions. (4)

• The bigger the positive ion, the weaker the bond (increased ionic radius down the group)

• The more electrons donated to hold the positive ions, the greater the electron density- so stronger (increase electrons being donated across period)

Describe the properties of metallic bonds.(3)

1. They have high melting points as metal are giant structures of atoms that have strong electrostatic attractions which needs more energy to overcome. (the melting point is related to the strength)

2. Electrical conductivity- conductor to electricity as there are free electrons able to carry charges for current.

3. Ductile- have regular structure that slide over each other when being hit.