Fundamentals of Chemistry Flashcards
What 3 major particles form the atom?
List their charges and relative masses.
Proton (+ve charge, mass = 1)
Neutron (no charge, mass = 0)
Electron (-ve charge, mass = 1)
Describe the arrangement of protons, neutrons and electrons in an atom.
Protons + neutrons in nucleus.
Electrons orbit the nucleus and are held in place by electrostatic attractions.
Describe the elemental composition.
Include mass number and atomic number.
Mass number
Element
Atomic number
What is the name of two atoms which:
Contain the same number of protons, different number of neutrons and have different atomic masses.
Isotope
When are atoms most stable?
When their outer-most orbital is full.
When an atom gains/loses electrons, creating a charge, it is known as what?
An ion.
Describe what occurs during ionic bonding.
Electrons are transferred between metals and non-metals.
Describe what happens during covalent bonding.
Electrons are shared between two or more non-metals.
What does the term valency relate to?
The number of covalent bonds an atom can make.
When do dative covalent bonds occur?
When both electrons of a pair are donated by one atom.
Creates one atom with positive charge and one with negative charge because the electron has been left behind and only the nucleus moves (contains protons and neutrons).
What form of bonding produces a charged ion?
Dative covalent bond.
What determines the shape of a covalent bond?
The number of electron pairs in the outer shell of the central atom.
TRUE OR FALSE:
Lone pairs repel more than shared pairs (give an angular structure).
TRUE
Define the word electronegativity.
Measure for attraction for electrons in a bond - capacity to pull.
When do atoms form polar bonds?
Polar bonds are formed when atoms have different electronegative charges -> more electronegative = negative charge.
Dipole example = HCl
Why does linear molecular shape matter?
Dipole forms at each end.
Charge cancelled out.
Non-polar molecule.
Example = CO2
Why does angled molecular shape matter?
2 dipoles at the lower end.
Strong +ve/-ve pull.
Polar molecule.
Example = H2O
Why are polar molecules important in biology?
Soluble in water.
Non-polar molecules are not easily dissolved in blood/urine (helps detect performance enhancing drugs).
Determines ability for transport in/out cells.
What are intermolecular forces?
Weak bonds formed between atoms, driven by temporary/permanent polarisation.
What is the importance of Van der Waals forces?
Electrons orbit the nucleus randomly, creating a cloud of negative charge ->
Clusters form and the molecule can be attracted to the positive end of another molcule.
Van der Waals forces have what affect on boiling point?
The stronger the Van der Waals force, the higher the boiling point.
Hydroxyl groups are the most simple. Why?
Oxygen bonded to hydrogen and organic molecule (e.g. carbon chain).
Polar bond between O and H.
Amine groups all contain what atom with a lone pair of electrons?
Nitrogen.
Carbonyl groups contain a carbon bonded how to an oxygen and two side chains?
Doubly bonded.
