Unit 1 Flashcards
Volume Units
3 -1
cm s
Mass Units
-1
gs
Concentration Units
-1 -1
moll s
What is Enthalpy?
A measure of the energy stored in a chemical
Exothermic Reaction
The products have less energy than the reactants.
Give out energy.
Endothermic Reaction
The products have more energy than the reactants.
Take in energy.
What does Heterogenous mean?
Different state
What does homogenous mean?
Same state
How could you distinguish between metals and non-metals?
Conductivity test
What is the Activation Energy (Ea)?
The minimum kinetic energy reactants need in order to become products
What is the Activated Complex?
The unstable arrangement of atoms at the peak of the Energy diagram
What does a catalyst do?
Speeds up the reaction
What happens to the nuclear charge as you go across a period and down a group?
As you got across the PT the nuclear charge increases.
As you go down a group the number of energy levels increases but the number of outer electrons stays the same
What is the trend in atomic size/volume as you go across the PT and down a group?
The atomic size decreases across a period as the nuclear charge increases pulling outer electrons closer to the nucleus.
Down a group atomic size increases as there are more energy levels.
What happens to the Ionisation energy as you go across a period and down a group?
Across a period the ionisation energy increases as the nuclear charge increases holding the outer electrons closer.
Down a group the ionisation energy decreases as the outer electrons are further away from the effect of the nucleus. There is also a screening effect from the inner electrons which shields the outer electrons from the full nuclear charge.
What is the 1st Ionisation energy?
The energy needed to remove the first mole of electrons.
What is the 1st, 2nd and 3rd Ionisation energy of Magnesium?
+ - -1
1st- Mg(g) ➡️ Mg (g) + e 744kJmol
+ 2+ - -1
2nd- Mg (g) ➡️ Mg (g) + e 1460kJmol
2+ 3+ - -1
3rd- Mg (g) ➡️ Mg (g) + e 7750kJmol
Why is there such a large jump in the third Ionisation energy of Magnesium?
Because the third electron if pulled off a full outer energy level which is closer to the nucleus
What is Electronegativity?
A measure of atoms attraction for electrons in a bond
What happens to the Electronegativity as you go across a period and down a group?
Across a group the Electronegativity increases as the growing nuclear charge pulls bonding electrons closer.
Down a group the Electronegativity decreases as the bonding electrons are further away from the nucleus and there is a screening effect from the inner electrons.
Average Rate
Change in volume/time taken
Change in mass/time taken
Change in concentration/time taken etc.
What is intramolecular bonding?
These are the bonds between atoms inside molecules
E.g. H - Cl
⬆️
intra
What is Covalent bonding?
Covalent bonds occur in non-metal atoms, these share their outer electrons
What is pure covalent bonding?
When each atom has the same electronegativity values, so the electrons are shared equally
