Semester 1: Chemistry Flashcards
atom
the smallest particle of a chemical element that can exist.
element
are composed of all types of atoms and have specific chemical properties.
atomic number
number of protons
=number of electrons
Mass number
neutrons and atom
isotopes
different atoms are same element if they have same amount of protons
groups
go down
have similar chemical properties
same number of electrons in the outershell
periods
go across
have same number of electron shells being filled
have same physical properties
transition metals
have similar physical properties and can fro, different ions, have similar chemical properties
Core charge
the attractive force of the nucleus and valence electrons
no. of protons - no. of inner electrons
down a group remains consistent
left to right increase due to valence electrons more attracted to nucleus
atomic radius
a measurement of the size of atoms. It is the distance from the nucleus to the valence shell electrons.
gets bigger going down and smaller as you go across
bigger because shells are added
decreased across because increasing nuclear charge
lowest energy electron shells
closest to nucleus, they fill first
Orbital shells
s:2
p:6
d:10
f:14
ion
An ion is an atom or group of atoms that has a
positive or negative charge.
Nonmetals tend to form anions.
Metals tend to form cations.
Why are elements in the periodic table arranged in order of atomic number rather than relative atomic mass?
No two elements can have the same atomic number\Atoms are listed in the periodic table in order of atomic number because the atomic number determines the number of electrons, and this in turn sets the properties that make each element unique. Relative atomic mass does not relate directly to either the atomic number or the electron number.
Explain the relationship between electronegativity and core charge.
The greater the core charge of an atom, the greater the electronegativity.
electronegativity
the ability of an atom to attract electrons in a molecule.
down a group decreases valence electrons are less strongly attracted to the nucleus
valence electrons are more attracted to nucleus so increases
metals
Reactivity of metals increases down a group
Reactivity of metals decreases across a period
non metals
decreases going down
increases acrosses period
metallic bonding
These electrons are called delocalised electrons. The electrostatic force of attraction between the negatively charged delocalised electrons and the positively charged metal cations holds the structure together.
Metallic bonding properties
high melting and boiling point
mallueable
ductile
spoon to hot to hold
The delocalised electrons in the metal spoon obtain energy from the boiling mixture and move quickly. These electrons move freely throughout the spoon, colliding with other electrons and metal ions, transferring energy so that the spoon becomes warmer and, eventually too hot to hold
copper conducts elctricity
When a current is applied to the copper wire, the delocalised electrons (free moving electrons) move from one end to the other and so the copper wire conducts electricity
ionic compound
An ionic compound is formed when a metal atom donates one or more electrons to a non-metal.
electrovalency
The charge on an ion is known as its electrovalency.
ionic structure
Ionic compounds are poor conductors of heat and electricity as solids, as there are no free charged particles that can transfer the charge.
Covalent bonding
Nonmetal + nonmetal
Sharing of electrons
have low melting and boiling points
be liquid, gas, or soft solids at room temperature
alkanes
single bond 2n+2
alkenes
double bond 2n
alkynes
triple bond 2n-2
ionisation
Ionisation energy is the least amount of energy needed to remove an electron from an atom or ion in the gas phase.
AB → A + B
decompisition
General: A + B → AB
synthesis
AB + C → AC + B
single displacement
AB(aq) + CD(aq) → AD(s) + CB(aq)
water and one solid
double displacement or precipitate
AB + CD → AD + CB
double displacement
CH4(aq) + 2O2(aq) → CO2(aq)+ 2H2O(l
combustion
HA(aq) + BOH(aq) →AB(aq)+ H20(l
acid base neutralisation
OH evident
electrostatic attraction
attractive or repulsive forces between particles that are caused by their electric charges
Monatomic
only one atom in molecule
Lattice
3d strucuture
