Atomic structure and Isotopes Flashcards
What are isotopes?
Atoms of the same element with the same number of protons but different number of neutrons.
Relative atomic mass definition
-The weighted average mass of an atom of an element
-Taking into account its naturally occurring isotopes
-Relative to 1/12 the mass of carbon 12
Relative molecular mass definition
-The mass of that molecule compared to 1/12 the atomic mass of an atom of carbon 12
What is an orbital
A bit of space that an electron moves in
SPDF NUMBER OF ORBITALS AND MAX ELECTRONS
-S=1 2
-P=3 6
-D=5 10
-F=7 14
Ionic bonding is…
A result of an electrostatic force of attraction between oppositely charged ions.
Why are ionic compounds solid at room temperature?
At room temperature there is not enough energy to overcome these strong electrostatic forces of attraction.
What else does ionic attraction depend on?
-Ions that contain ions with greater ionic charges
-The size of the ions
What two processes do solubility require in ionic compounds?
-The ionic lattice must be broken down
-Water molecules must attract and surround the ions
(solubility) The higher the ionic charges in an ionic compound the..
Less soluble the substance is
Why can’t solid ionic compounds conduct electricity?
-The ions are in a fixed position in the giant ionic lattice
-There are no mobile charge carriers.
What is a covalent bond?
A shared pair of electrons
How does bonding work in covalent molecules?
Atoms with covalent bonds are held together by electrostatic force of attraction between nuclei and shared electrons.
What other things do covalent bonds depend on?
-How much the outer atomic orbitals of the bonded atoms overlap
-How strongly the atomic nuclei are attracted to the shared pair of electrons.
How do you measure the strength of a covalent bond?
Average bond enthalpy
What is co-ordinate/Dative covalent bonding?
-When one atom provides both the electrons.
How do electrons repel each other?
Electrons are negatively charged so charged clouds repel each other until they are as far apart as possible.
What is electronegativity
-The attraction of a bonded atom for the pair of electrons in a covalent bond.
What is the trend of electronegativity?(WHY)
Going across the period electronegativity increases because…
-The nuclear charge increases
-Atomic radius decreases.
What type of covalent bond is in a C-C molecule?
A pure covalent non polar bond
Because both atoms have the same electronegativity
What type of covalent bond is found in a C-F bond?(WHY)
-It is a polar covalent bond
-Because there is a difference in electronegativity
-The greater the difference in electronegativity the more polar the covalent bond is
How is a polar molecule formed?
When charge is distributed unevenly over a whole molecule and so will have a permanent dipole.
A non-polar molecule is when…
polar molecules are arranged more symmetrically the dipoles cancel out
A polar molecule is when..
Bonds are arranged so that they roughly point at the same direction so they don’t cancel out.
What are covalent and intermolecular forces responsible for?
-Intermolecular=physical properties
-Covalent bonds=Chemical properties
Induced dipole- dipole (London forces)
London dispersion forces arise due to temporary dipoles that are formed when electrons in a molecule are unevenly distributed.
