Atomic Structure Flashcards
(13 cards)
2 Ionisation Techniques
Electron Impact
Electrospray ionisation
Molecules ionised by electron impact are known as?
Molecular ion
What ionisation method is this?
The sample X is dissolved in a volatile solvent and injected through a fine hypodermic needle to give fine mist. The tip of the needle is attached to the positive terminal of a high-voltage power supply. The particles are ionised by gaining a proton from the solvent as they leave the needle producing XH+ ions
Electrospray ionisation
What’s a molecular ion?
A molecule that results from the loss of an electron
What’s protonation
Protonation is the adding of a proton to an atom/molecule
What’s relative atomic mass?
The average mass of an atom/isotope compared to 1/12 the mass of C12
What’s electronegativity
The ability of an atom to attract a bonding pair of electrons in a covalent bond
What does polar mean
Polar bonds have a permanent uneven distribution of electron density caused by a large difference in electronegativity
The strongest intermolecular force
Hydrogen bonding - caused by hydrogen covalently bonded to N/O/F
Permanent dipole-dipole forces
IMF caused by large difference in electronegativity between two elements in a covalent bond (in polar bonds but not H bonded to NOF)
2nd strongest
Van Der Waals forces
Found in every simple covalent compound
Caused by random movement of electrons causing a temporary dipole
The weakest IMF
Affected by larger electron cloud and more surface area for intermolecular contact
Order of melting point
Giant covalent
Giant ionic
Giant metallic
Simple covalent
Bond Angles
2 Linear - 2(bonding pairs),2(lone) - 180°
3 - Trigonal planar - 3,0- 120°
4 - Tetrahedral - 4, 0 - 109.5°
4 - Trigonal Pyramidal - 3,1 -107°
4 - Bent - 2,2 - 104.5°
5 - Trigonal Bipyramidal - 5, 0 - 120°&90°
6 - Octahedral -6,0 - 90°