Chemistry: Structure and Bonding

What is the smaller number of an element in the periodic table?

The atomic number, which represents the number of protons in an atom's nucleus.

What is the larger number of an element in the periodic table?

The mass number, which is the total number of protons and neutrons in an atom.

what are the horizontal rows on a periodic table called and what do they represent?

They’re called periods and they represent the number of electron shells an atom has.

what are the vertical rows on a periodic table called and what do they represent?

They’re called groups and they represent the valency of the atom. This is the amount of electrons in the outer shell.

What is an isotope?

atoms of an element that has the same number of protons but a different number of neutrons.

What is an ion?

When an atom gains or loses electrons, an ion is formed. 

If there are more protons than electrons what is it called?

a CATION.

If there are more electrons than protons?

an ANION.

What is an Ionic Bond?

An ionic bond is an electrostatic attraction between oppositely charged ions.

What type of atoms are ionic bonds made from?

Formed from metal and non-metal atoms.

How is an ionic bond formed?

Its formed when electrons are transferred from a metal atom to a non metal atom such that both atoms form a FULL OUTER SHELL.(like the noble gases)

What are ionic compounds normally?

Solid crystalline structures.

How is size of an atom determined and ratio?

The amount of shells in the atom. Ratio of ions in an ionic lattice is always constant.

What’s the melting and boiling point like in an ionic compound?

They have high melting and boiling points.

Why are ionic compound’s melting and boiling points like this?

It requires a large amount of HEAT energy to break the many strong oppositely charged electrostatic attractions between the oppositely charged ions.

What is strength of an ionic compound like and why?

They are very brittle. This is because when force is applied the layers shift which puts like charges next to each other, causing repulsion and the crystals break apart.

What is the solubility of an ionic compound like?

Some ionic compounds can dissolve in water because the water molecules cluster around the ions and rip them off the lattice. POLAR molecules

What is the conductivity of solid ionic compounds like?

They cannot conduct electricity because their ions are in fixed positions in the lattice and can’t carry a charge.

What is the conductivity of molten and aqueous ionic compounds like?

Aqueous and molten ionic compounds can conduct electricity because the ions are free to move and can carry a charge.

What is a covalent bond?

A covalent bond is an electrostatic attraction between a shared pair of electrons and the nuclei of 2 atoms.

How can you identify a covalent bond?

A covalent bond is between non-metal atoms.

How does a simple covalent structure differ from a giant covalent structure?

simple covalent structures have a small, fixed number of atoms joined by strong covalent bonds.

How does a giant covalent structure differ from a simple covalent structure?

giant covalent structures have a very large number of atoms joined by strong covalent bonds to form a network.

What happens when a simple covalent structure changes state?

The covalent bonds are not broken but only the weak forces of attraction between molecules. (Called intermolecular forces)

What are the physical properties of simple covalent structures?

• Has a low melting and boiling point as low heat energy required to break weak intermolecular forces of attraction.

• Some simple covalent structures are soluble in water.

• Simple covalent stuctures do not conduct electricity as there are no free moving charge carriers.

What is an allotrope?

Allotropes are different structural forms of the same element.

What are some popular examples of allotropes of carbon?

Diamond and graphite/graphene

What is the structure of diamonds?

Carbon in diamonds forms 4x covalent bonds. Every carbon is using all 4 of its outer electrons for bonding (localised). Diamonds are in a tetrahedral structure which is repeated millions of times. Giant Covalent.

What are the properties of diamond in terms of strength?

• Diamonds are strong as they have a stable structure, rigid arrangement of atoms in a regular, repeating tetrahedral shape.

• It would require lots of energy to break the multiple covalent bonds.

What are the properties of diamond in terms of as an insulator and its sublimation point?

Diamonds have no free moving charge carriers as all electrons are involved in bonding.

High sublimation point as it requires a large amount of energy to break the many strong covalent bonds.

What is the shape of the structure of graphite?

Each carbon in graphite forms 3 covalent bonds.

The carbon is arranged in hexagons which lock together to form layers.

How are layers of graphite held together?

Through weak forces of attraction.

How are electrons in graphite?

Each carbon uses 3 e- (covalent) for bonding so 1 e- is therefore free to move within the layer. DELOCALISED

What’s the strength property of graphite?

Graphite is a lubricant, which means when force is applied, the layers of graphite can move on the weak forces of attraction causing the layers to break and snap easily.

What are some other properties of graphite?

graphite is an electrical conductor as free moving, delocalised electrons can carry a charge.

Graphite also has a high melting and boiling point as a lot of heat energy is required to break the many strong covalent bonds in the GIANT structure.

What is a metallic bond?

A metallic bond is an electrostatic attraction between positive metal ions and a sea of delocalised electrons.

What type of lattice structure are ionic compounds?

Ionic compounds are always giant.

What type of lattice structure are metallic compounds?

Metallic compounds are always giant.

How are metallic structures held together?

The attraction between the positive metal ions and free moving electrons keep the structure together.

What is a metal’s melting and boiling point like?

High MPT/BPT as it requires a large amount of heat energy to break the many strong metallic bonds. (Always define a metallic bond when answering.)

What is the conductivity like in metal structures?

Metals are very good conductors of heat and electricity as there are many free moving, delocalised electrons which can carry a charge.

They conduct heat well as when they heat up the ions vibrate more vigouresly and the electrons move more rapidly.

How are metals strength wise?

Metals are malleable, ductile and sonorous.

When layers shift, the metallic bonds are not broken because the electrons are free to move.