Chemical Sciences and Quantitative Skills Flashcards
What is the Atomic Number?
The number of protons in a atom. (determines what element it is).
What is an Isotope?
Different forms of one element with different Atomic Masses due to different numbers of neutrons. (An example could be carbon-12 and carbon-14).
What are the Group 1 elements?
Hydrogen (H), Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs), and Francium (Fr).
Why are Group 1 elements electro positive? How does this affect their behaviour?
They have 1 electron in their outermost shell. This means they a high tendency to donate their outer electron and form positive ions. (e.g. Na+,K+)
What are the Group 2 elements?
Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), and Radium (Ra).
What shape is the S orbital?
Spherical
What shape is the P orbital?
Dumbbell shaped
What are the Group 8 (Noble Gasses) elements?
Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), and the radioactive Radon (Rn).
Why are Group 8 (Nobel Gasses) unreactive?
Because they have full outer shells. Meaning they are stable.
What are the Group 7 (Halogens) elements?
Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I), Astatine (At), and Tennessine (Ts).
Why are Group 7 (Halogens) electro negative?
Because they have 7 electrons in their outer shell and pull off or share electrons from other elements to complete their shell. (e.g. NaCl,KBr).
Why does electronegativity decrease as you go down Group 7?
Greater number of shells between the positively charged nucleus and negatively charged electrons it is trying to attract. Increased distance.
What are Organic Compounds?
Compounds that contain Carbon covalently boded to Hydrogen, Nitrogen and/or Oxygen.
What are the Orbitals?
1s
2s 2p
3s 3p 3d
4s 4p 4d 4f
5s 5p 5d 5f
6s 6p 6d
7s 7p
8s
What is spin pairing of electrons?
Where 2 electrons occupy an orbital and due to them both being negatively charged they have to spin in opposite directions to avoid strong repulsion forces. (Pauli exclusion principle)
How many electrons do the s, p, d and f orbitals hold?
2, 6, 10 and 14 respectively.
What are the 5 most electronegative elements?
Fluorine, Oxygen, Nitrogen, Chlorine, Bromine, Iodine, Sulfur, Carbon, and Hydrogen.
What are degenerate orbitals?
When orbitals have the same energy level. (e.g. the 3 orbitas in the 2p subshell).
What is Valence?
The electrons in the outermost shell, or energy level, of an atom. This determines the way they interact with other atoms and compounds.
What is Hund’s Rule?
The idea all orbitals would need to be half filled (1 electron) before being completely filled (2 electrons). When completely filled they need to be spin paired to avoid repulsion.
What is Oxidation state?
Oxidation is the number of electrons which have been removed from an element (producing a positive oxidation state) or added to an element (producing a negative oxidation state) to reach its present state.
What is a delocalised pi system?
When the p and s orbitals overlap and resulting in free electrons that are able to move over more than 2 nuclei.
What is promotion?
When an electron absorbs a photon to jump form a lower energy level orbital to a higher energy level orbital.
Why can Phosphorous and Sulphur form 5 and 6 bonds respectively?
Due to the presence of vacant 3d orbitals which get occupied creating more bonds.
What is hybridisation?
When 2 separate orbitals fuse to form a new orbital e.g. sp2 orbital.
What is the shape of the sp3 orbital?
Lopsided Dumbbell
What is the Tetrahedral bond angle?
109.5, This is due to electron pair repulsion.
What is the Linear bond angle?
180
What is the Trigonal planar bond angle?
120
What are the Trigonal Bipyramidal bond angles?
120,90
What is the Octahedral bond angle?
90
What is a Sigma bond?
The strongest type of covalent chemical bond formed by the head on overlapping between atomic orbitals.
What is the name for triple bonded compounds?
Alkynes
What does Ortho, Meta and Para mean in relation to cyclic compounds?
The position of side chains in relation to the primary counting/functional group point on the ring.
Ortho- Next point over from primary
Para- Opposite to primary
Meta- Obtuse angle from primary point.
What is the Functional group order of priority when counting?
1.Carboxylic Acid- COOH
2.Ester- RC=OOR
3.Amide- NH
4.Nitrile- CN
5.Aldehyde- C=OH
6.Ketone- =O
7.Alcohol- OH
8.Amine- NH2
What is a Systematic error?
When a measurement is precise however isn’t accurate e.g. a stop watch is 2 seconds fast all the results will be 2 seconds faster than the accurate value.
Name 6 types of Systematic error.
1.Miscalculations
2.Operator Errors
3.Instrumental Limitations
4.Environmental Influences
5.Sample Size
6.Unrepresentative Sample
How do you establish the purity of Aspirin?
Recrystallisation or Visual Spectrophotometer
How would you detect impurities in Aspirin?
The Mass Method or High Performance Liquid Chromatography
What is the Diffusion Coefficient equation?
D= RT/6PI nrN
D= Diffusion Coefficient (m^2 s^-1)
R= Gas Constant (8.31)
T= Temperature (Kelvin)
n= Viscosity
r= Radius of particle
N= Avogadro’s number
Henderson Hasslebanch equation?
Ph= pKa +log((salt concentration)/(acid concentration))
pKa= -log of dissociation constant
