Bonding, Structure and Properties of Matter Flashcards
What are ionic bonds formed between?
Metal and non-metal elements.
What do strong electrostatic attraction do?
Attracts oppositely charged ions together in an ionic bond.
What do ionic compounds form on a large scale?
Ionic lattices.
What are the limitations of using dot and cross, ball and stick, two and three dimensional diagrams for ionic and covalent bonding?
› they don’t show the structure of the compound.
› the size of the ions aren’t shown.
› arrangement.
CHECK PAGE 51 IN CHEMISTRY REVISION GUIDE TO LEARN EMPIRICAL FORMULA.
CHECK ANSWERS AFTER TRYING IT OUT.
What are the 3 properties of ionic compounds?
› high melting points and boiling points - lots of energy needed to overcome many strong bonds.
› when solid, the ions are held in place so compounds can’t conduct electricity.
↳ when they are molten or dissolved, the ions are free to move and they’ll carry electric charge.
› giant ionic lattice structure - electrostatic forces of attraction between oppositely charged ions act in all directions.
Why do ionic compounds have high melting points?
› the ions have a closely packed regular lattice arrangement.
› they are very strong electrostatic forces of attraction between oppositely charge ions in all directions in the lattice.
Where are covalent bonds formed?
Between non-metal elements.
What is a covalent bond?
A shared pair of electrons between two non-metal atoms.
[it can happen in non-metals compounds and non mental elements]
Give 3 properties of simple covalent compounds.
› simple molecular structures.
› held together by very strong covalent bonds - forces of attraction between these molecules are very weak.
› most molecule substances are gases or liquids at room temperature.
›as they get bigger, the strength of the intercellular forces increases so more energy is needed to break them and the melting and boiling points increases.
› don’t conduct electricity as they aren’t charged so they are no free electrons or ions.
Why do simple covalent compounds not conduct electricity?
They aren’t charged so they are no free electrons or ions.
Why do simple covalent compounds have a low melting and boiling point?
Molecules are easily parted from each other.
What are the 3 different types of of giant covalent structures?
Diamond, graphite and silicon dioxide.
Describe a diamond giant covalent structure.
Each carbon atom forms four covalent bonds in a very rigid giant covalent structure.
Describe a graphite giant covalent structure.
Each carbon atom forms three covalent bonds to create layers of hexagons. Each carbon atom also has a delocalised (free) electron.
Describe a silicon dioxide giant covalent structure.
Sometimes called silica, this is what sand is made of. Each gram of sand is one giant structure of silicon and oxygen.
What are the 3 properties of a diamond covalent structures?
› really hard - four covalent bonds.
› very high melting point - covalent bonds take a lot of energy to break.
› doesn’t conduct electricity as it has no free electrons or ions.
What are the 4 properties of a graphite covalent structures?
› three covalent bonds creating sheets of carbon atoms arranged in hexagons.
› no covalent bonds between layers and held together weakly so free to move over each other.
↳ soft and slippery.
› high melting point.
› one electron thats delocalised (free) and can move so it conducts electricity and thermal energy.