test 1 Flashcards
(34 cards)
what does the mass number equal to?
the total number of protons and neutrons in an atom
what is an isotope?
an element with the same number of protons and a different number of neutrons
how are isotopes similar/different?
same chemical properties, different physical properties (mass)
how to calculate relative atomic mass?
(isotopic mass * % abundance) (isotopic mass * % abundance) / 100
periodic table trend: ionisation energy
is the amount of energy required to remove the highest-energy electron
from a neutral atom.
increases across a period and up group because non-metals don’t want to lose electron
periodic table trend: electronegativity
the ability to attract an electron. increases across period and up group. non-metals have a much higher ability to accept electrons.
periodic table trend: atomic radius
increases going right to left from a period and going down. Fr being the biggest. it is the distance from the nucleus to the valence shell
group number?
number of valence electrons
period?
number of electron shells
what happens when electrons are excited?
the valence electrons jump from ground state to excited state, when they return to ground state, they emit visible light.
metallic bonding?
the bonding between two metals. it is a lattice of metal cations surrounded by a sea of delocalised electrons
properties of metallic bonds?
- conductivity
(due to mobile charged particles in electricity) - malleability/ductile
(can push the arrangement of the atoms across - will stay within structure due to delocalised electrons - when one layer moves, the ions are still held together by electrons) - high m/b points (bond is very strong)
- lustrous (when ray of light hits electrons, becomes excited, releases light)
how are metals reactive?
by shedding electrons, the easier they can lose the electron, the more reactive
which metals react with acids?
all
which metals react with water?
most 1, kind of group 2
which metals react with oxygen?
1, 2 and some transition metals
what is ionic bonding?
a bond between a non-metal and a metal. metal donates electron to non-metal. opposite charge makes them attract
what shape is an ionic bond?
a three dimensional lattice with positively and negatively charged atoms held together by a strong electrostatic force
properties of ionic bonds?
- high m/b points - attraction between bonds - lots of energy needed to break
- hard but brittle
(molecules are different sizes, can’t slide, if they do they’ll break. if they slide, the same charge atoms will meet and repel, causing to break) - not conductive in solid state (no mobile electrons) - conductive in solution or liquid (water interrupts bond - break apart and move around)
properties of non-metals?
- low m/b points (inTERmolecular bonding in covalent bonds can be very weak)
-not conductive (no delocalised electrons)
intramolecular v intermolecular bonds?
intramolecular are the bonds between the atoms in the molecule, intermolecular are the forces amongst molecules. inTRAmolecular forces are very strong.
what is a covalent bond?
share electrons between two non-metals, held together by their mutual attraction towards the electrons
properties of covalent bonds?
- low m/b points (weak inTERmolecular forces)
- have an odour
- non-conductive (non mobile charged particles)
- insoluble in water, soluble in non-polar solvents (petrol)
what is chemical energy?
chemical potential energy stored between the bonds
