atoms, ions and compounds- chapter 2 Flashcards
what is an atom made up of
nucleus, protons, neutrons and electrons
what has the smallest mass of the subatomic particles
electron- has 1/1836th the mass of a proton
what charge does a… have
1. proton
2. electron
3. proton
4. neutron
- positive
- negative
- equal but opposite the charge on an electron, the charges balance
- no charge
what is the relative charge of..
1. proton
2. neutron
3. electron
- 1+
- 0
- 1-
what is the relative mass of..
1. proton
2. neutron
3. electron
- 1
- 1
- 1/1836
every atom of the same element contains the…
…same number of protons
different elements contain atoms that have…
…different numbers of protons
what is the atomic number
the number of protons
what are isotopes
atoms of the same element with different numbers of neutrons and different masses
what is the mass number
number of protons+number of neutrons
what do isotopes of the same element have the same of
number of electrons
what does the number of neutrons have an affect on
has no effect on reactions of an element
what will small differences in physical properties be due to with higher mass isotopes
elements having a higher melting point, boiling point and density but chemical reactions are the same
what is an ion
a charged atom, number of electron is different from the number of protons
what are positive ions
cations, atoms with fewer electrons than protons, overall positive charge
what are negative ions
anions, atoms with more electrons than protons, overall negative charge
ions and atoms have the same number of … but a different number of …
protons
electrons
do atoms of the left of the periodic table lose or gain electrons
lose to form cations
do atoms of non-metals on the right side of the periodic table lose or gain electrons
gains to form anions
what are binary compounds
contains two elements only
what is a polyatomic ions
an ion may contain atoms of more than one element bonded together
what does an ionic compound contain
a cation and an anion
what are diatomic molecules
contains two atoms bonded together
what are formula units
for ionic compounds, the formula worked out from the ionic charges is used in equations
do covalent compounds have ions
no they don’t contain ions, most exist as molecules with a small number of atoms bonded together
what is relative isotopic mass
the mass of an isotope relative to 1/12th of the mass of an atom of carbon-12
what is relative atomic mass
the weighted mean mass of an atom of an element relative to 1/12th of the mass of an atom of carbon-12
what 2 things does the weighted mean mass take account of
the percentage abundance of each isotope
the relative isotopic mass of each isotope
what does a mass spectrometer show
the percentage abundances of the isotopes in a sample of an element
how does a mass spectrometer work
- sample is placed in mass spectrometer
- sample is vaporised and then ionised to form positive ion
- ions are accelerated, heavier ions move more slowly and are more difficult to deflect than lighter ions, so the ions of each isotope are separated
- ions are detected on a mass spectrum as a mass-to-charge ratio m/z, each ion reaching the detector adds to the signal, so the greater the abundance
what is m/z
relative mass of ion/relative charge of ion
