2.2 Atoms, Ions And Compounds Flashcards
Atomic Number
Number of protons in the nucleus of an atom.
Mass Number
Number of protons and neutrons in nucleus that form mass of an atom.
Electron
Subatomic particle with charge of -1 and mass of 1/1836 that occupies shells around nucleus.
Proton
Subatomic particle with charge of +1 and mass of 1 found in nucleus of an atom.
Neutron
Subatomic particle with charge of 0 and mass of 1 found in nucleus of an atom.
Ion
A charged atom where number of electrons is different from number of protons.
Isotope
Atom with same number of protons and electrons but different number of neutrons in the nucleus.
Relative Atomic Mass
Weighted mean mass of an atom of an element compared to 1/12 mass of carbon-12.
Relative Isotopic Mass
Weighted mass of an atom of an isotope when compared to that of 1/12 of an atom of carbon-12.
Formula of relative atomic mass
(% abundance x mass)+(%abundance x mass) /100
Cation
Atoms with fewer electrons than protons. Have an overall positive charge.
Anion
Atoms with more electrons than protons. Have an overall negative charge
Uses of mass spectrometer
-Monitoring breath of patients during surgery.
-Detecting banned substances in athletics.
-Analysing molecules in space.
How do mass spectrometers works
1) Sample placed in mass spectrometer.
2) Vaporised then ionised.
3) Ions are accelerated by electromagnetic plate.
4) Ions are detected with (m/z)mass to charge ratio. Larger abundance= larger the signal.
Ionisation in mass spectrometer.
Electron from electron gun knocks electron from substance,producing a cation.
M+e = M+ + 2e-
Acceleration in mass spectrometer
Negative plate attracts positive ion making the ion accelerate to bend round corner.
Deflection in mass spectrometer
Uses magnetic field. Higher the mass= stronger magnetic field needed to reach the detector.
Detection in mass spectrometer
Masses are determined for each ion by signal each ion produces by mass to charge ratio. Higher abundance=larger signal
What do peaks on mass spectra show?
Number of isotopes
What do the height of the peaks show in a mass spectra?
Abundance of each isotope.
What are binary compounds ?
Compounds that contain 2 elements only.
In ionic compounds, metal ion always comes first.
What are polyatomic ions?
Ions that contain atoms of more than one element bonded together.
Eg. NO3-, SO4 3+
What do some elements exist as?
Diatomic molecules containing 2 atoms bonded together.
Eg. O2 H2 Cl2
What are covalent compounds ?
Exist as molecules with small number of atoms bonded together, that share pairs of electrons. They do not contain ions.
Eg. CO2, H20
Formula of magnesium cation
Mg2+
Formula of sodium cation
Na+
Formula of potassium cation
K+
Formula of calcium cation
Ca2+
Formula of copper cation
Cu2+
Formula of aluminium cation
Al3+
Formula of silver cation
Ag+
Formula of zinc cation
Zn2+
Formula of ammonium (cation).
NH4+
Formula of phosphorous anion
P3-
Formula of sulphur anion
S2-
Formula of oxygen anion
O2-
Formula of chlorine anion
Cl-
Formula of bromine anion
Br-
Formula of iodine anion
I-
Formula of hydroxide anion
OH-
Formula of sulphate anion
SO4 2-
Formula of carbonate anion
CO3 2-
Formula of nitrate anion
NO3 -
