Topic 1 - Key concepts in Chemistry Flashcards
23
Na
11
what is the top number
The relative atomic mass
23
Na
11
what is the bottom number
the atomic number
What is the relative atomic mass?
The total number of protons and neutrons
What is the atomic number
The number of protons (therefore the number of electrons)
What are isotopes?
an element which can have different numbers of neutrons
Proton
Mass of 1
positive charge
electron
very small mass
negative charge
neutron
mass of 1
no charge
The equation for Relative atomic mass
(rm x ra) + another dpending on how many / total abundance
Electron configuration rules
The first shell can only contain 2 electrons
the shells after hold 8
fill from in to out
What do atoms think when they dont have a full outer shell?
They wanna be stable, so they want to chemically react.
what are bonds?
forces of attraction that holds the atoms together
what type of atom changes name when turning into ion? what ending?
Non- metals and ends with ide or ate
What is an ion?
an atom or group of atoms that have lost / gained electrons resulting in a net charge
What are cations
Metals will always loose electrons and become postively cvharged.
Wat are anions
A
Non metals will gain electrons and become negatively charg
Ionic bonding between
metal and non metal
Ionic Bonding vs Covalent Bonding
Covalent bonding between 2 non metals.
ionic is a metal and a non metal
What are ionic compounds
ionic compounds contain one or more cation paired with one or more anion
they are formed by the loss or gain of electrons
they are held together by strong electrostatic forces of attraction between opposely charges ions
Why do ions form lattice structures?
They are because the stong electrostatic forces let “billions” of ions to be packes together in this regular repeating structure
What does the ending ide or ate mean in a ion?
it shows the ion has oxygen and another element in it
Why do ionic compounds have such a high melting and boilig point?
there is strong electrostatic forces that hold them together, it takes alot of energy to break these bonds
When do ionic compounds conduct electricity?
WHen they are molten or dissolved in water
its the chargged ions that carry the current, so they need to be free to conduct
What 2 conditions must be met for a thing to conduct electricity?
It must contain charged particles
these particles must be free to move
What are simple molecular substances ?
molecules held together by covalent bonds
When are covalent bonds usually formed?
between 2 non metals sharing pairs of electrons
They are strong
How are the atoms in molecules held together?
the strong electrostatic forces of attraction between the nuclei and the shared electrons
how are ionic compounds electrically neutral?
the 2 components have balancing positive charge and negative charge
Why do ionic copounds only conduct when molten or in aqueous solution?
The particles to be free to carry the current for it is the charged ions that actually carry it.
What is the law of conservation of mass?
In a chemical reaction, mass is always conserved in a closed system
Concentration =
mass of solute in g/
volume of solution in dm3
Why may mass appear to be lost in an open system?
the products may be gases released into the air
What is the Empirical formula?
the simplest whole number ratio of atoms or ions of each element in a substence
As well as Empirical formula, what do simple molecules have?
A molecular formula
Molecular formula
the amount of atoms of each element actually in that molecule
What is the symbol for relative formula mass?
Mr
What is the symbol for relative atomic mass?
Ar