Atomic structure and periodic table, separating mixtures, bonding and structure Flashcards
What is an atom?
The smallest particle of a chemical element that can exist
What is an element?
A substance that cannot be broken down into any other substance
What is a compound?
A substance which is formed from identical molecules made of more than one element which are bonded together
In electronic configuration, how many electrons does the 1st and second shell always have?
1st= 2 2nd= 8
How do you draw electronic configuration of an element?
- Find the atomic number (this is the number of electrons)
- Write the element symbol
- Draw a circle, add electrons till shell is full
- Draw another circle; max of 8 electrons
- keep going until no electrons left
What are the properties of giant covalent structures?
- High melting and boiling points
- The compounds can be hard or soft
- Most compounds are insoluble with water
- Most compounds do no conduct electricity however some do
What properties do metals have?
- Good conductors of heat
- Good conductors of electricity
- Malleable
- Ductile
- High boiling points
- High melting points
What is a pure substance?
A single element or compound, not mixed with any other substance
How can we use melting point data to distinguish pure from impure substances?
An impure substance is a type of mixture, so melting points can be used to find out if a substance is pure of impure
What is a mixture?
Where two or more substances are combined, but not chemically
What is a mixture?
Where two or more substances are combined, but not chemically
How easy are compounds to separate?
Difficult as it usually takes a lot of energy to break the chemical bonds
What would you use filtration, evaporation, and crystallisation for?
Filtration- When you have an insoluble solid in a liquid
Evaporation- When you have a soluble solid dissolved in a solvent
Crystallisation- When you have a soluble solid dissolved in a solvent
What would you use chromatography, simple distillation and fractional distillation for?
Chromatography- When you have at least two soluble solids dissolved in a solvent
Simple distillation- When you want to separate the solvent from a solution
Fractional distillation- When you have two or more miscible liquids
What is ionic bonding?
A type of linkage formed from the electrostatic attraction between oppositely charged ions in a chemical compound
