Chemistry Level 6 - Lectures 2 and 2b Flashcards
what particles make up an atom?
proton
electron
neutron
where is the proton found?
inside the nucleus
where is the electron found?
orbiting the nucleus
where is the neutron found?
inside the nucleus
what is the mass of a proton?
1 a.m.u.
what is the mass of an electron?
0 a.m.u.
what is the mass of a neutron?
1 a.m.u.
what is the charge on a proton?
1+
what is the charge on an electron?
1-
what is the charge on a neutron?
0
what does the atomic number consist of?
protons and electrons
what does the mass number consist of?
protons and neutrons
what are properties of Group 1 elements?
- reactive
- stored under oil
- conduct electricity
- ductile
what are properties of Group 7 elements?
- reactive non-metals
- exist as diatomic molecules
- readily reacts with metals
- poor electrical conductors
what are properties of Group 0 elements?
- gasesous
- unreactive
- monatomic gases
what is used to measure the size of an atom?
covalent radii
explain the trend in atomic size when going across a period
- atoms still have same number of occupied energy levels
- increase of nuclear charge
- increase positive nuclear charge causes an increase in attraction to the electrons - results in nucleus pulling in electrons tighter
- covalent radius decreases
explain the trend in atomic size when going down a group
- nuclear charge increases
- one more energy level is occupied by electrons
- causes shielding effect to outer electrons from the nucleus
- covalent radius increases
what is ionisation energy?
the energy required to turn an atom into an ion
explain the trend in ionisation energy when going down a group
- electron removed from outermost layer of electrons which is increasingly distant from the nucleus
- electron less attracted to nucleus and so easier to remove
- ionisation energy decreases
- outer electron is shielded from the nuclear charger by inner layers of electron
explain the trend in ionisation energy when going across a period
- electron being removed is in the same layer whilst nuclear charge increases
- outer electrons are more strongly attracted to nucleus as you move across a period
- ionisation energy increases
explain the trend in electronegativity when going across a period
- number of charges on the nucleus increases
- causes electrons to be more strongly attracted to the nucleus
- electronegativity increases
explain the trend in electronegativity when going down a group
- electrons are further away from the nuclear attraction
- electronegativity decreases
