Electrons bonding and structure Module 2 Flashcards
Order of filling up of subshells?
1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 (writen before 4s) 4p^6 4d^10 4f^14
Label the notation for electronic configuration?
number in front is energy level
letter in middle is the subshell
number it’s to the power to is the number of electrons
Features of an orbital?
It’s a bit of space that an electron moves in
Can hold up to 2 electrons with opposite spin (spin-pairing)
Orbitals within the same sub-shell have the same energy
What shape are s orbitals?
Spherical
What shape are P orbitals?
Dumbbell
How do you fill up orbitals?
Put an arrow in each box facing one direction, and once every box is filled in subshell can start adding arrow in opposite direction to the orbitals
All orbitals must be filled before going to next subshell
Must take into account how many electron there actually is in ions
What is an ionic bond?
The electrostatic attraction between 2 oppositely charged ions
How to draw a dot and cross diagram?
Draw every chemical with only it’s outer ring of electrons
Draw arrows from element which is donating the electrons to the other atom(s)
Redraw both of them with the positive ion having empty outer shell and a bracket with it’s charge, and negative ion with full outer shell (including different shaped electrons from other atom)
Remember number in front if there’s more than 1
Describe Sodium chlorides giant ionic lattice?
Na+, and Cl- ions packed together alternately in a regular structure called a lattice
“giant” as it’s a repeating structure
Each ion is electrostatically attracted in all directions to ions of the opposite charge
Why do ionic compounds conduct electricity when molten or dissolved but not when solid?
The ions in a liquid are mobile (and they can carry charge)
In a solid they aren’t mobile
Why do ionic compounds have high boiling and melting points?
Giant ionic lattices held together by strong electrostatic forces which require a lot of energy to break
Why do ionic compounds tend to dissolve in water?
Water molecules are polar, so attracted to the charged ions
They pull the ions away from the lattice causing it to dissolve
Covalent bond definition?
Strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms
What’s the average bond enthalpy?
Amount of energy required to break a covalent bond
What’s a dative covalent bond?
Where both electrons come from one atom
Eg when ammonia has a H+ ion added to it to for a ammonium + ion, both electrons come from the Nitrogen
When drawing dot and cross arrow goes towards H+, instead of just a normal line
What determines molecular shape?
The electron pairs around the central atom
Order of the size of angles produced by electron pairs?
Lone pair- Lone pair is biggest
Lone pair-Bonded pair second
Bonded pair- Bonded pair smallest
What do you do if there is a double bond when predicting the shape of a molecule?
Treat them the same as single bonds
What does 2 electron pairs around the central atom produce?
Linear molecule
180 degrees
3 bonded pairs around the central atom?
Trigonal planar
120 degrees
4 bonded pairs around central atom?
Tetraherdral (Tripod shaped, use lined wedge and filled in wedge)
109.5 degrees
3 bonded pairs and one lone pair around central atom?
trigonal pyramidal, (lone pair at top, everything splits off evenly from it downwards, use lined wedge, and filled in wedge)
107 degrees
2 bonded pairs and 2 lone pairs around central atom?
nonlinear shape (V shaped) 104.5 degrees
5 bonded pairs around central atom?
Trigonal bipryamidal
Around central atom there is a straight line going through, and perpindicular to this there is a triangle of atoms (use both wedges in this)
Producing 90 degree angles and 120 degree angles)
6 Bonded pairs around central atom?
Octahedral (Use 2 lined wedge, and 2 filled in wedge)
All angles 90 degrees
Definition of eletronegativity?
An atom’s ability to attract the electron pair in a covalent bond
Order of electronegativity of elements from highest to lowest of ones we need to know?
Flourine Oxygen Chlorine Nitrogen Carbon Hydrogen (very small difference between carbon and hydrogen means doesn't create polar bonds)
Fat Oscar Cums near carrot heavily
What happens to covalent bonds when one atom has a much larger electronegativity, and what happens if the atoms are the same?
Electrons pulled to atom with the higher electronegativity making the bond polar ( delta negative and delta positive), Permanent dipole has been formed ( be careful because polar bonds may cancel each other out like in CO2 so no permanent dipole formed)
If they are the same then bond isn’t polar as attract the electrons equally so no permanent dipole formed
Are intermolecular forces very weak or very strong?
Very weak
Order of strength of the intermolecular forces from strongest to weakest?
Hydrogen bonding
Permanent dipole-dipole interactions
Induced dipole-dipole interactions ( London forces)
How do induced dipole-dipole forces form?
Found between all atoms and molecules
Electrons in charge clouds are moving very quickly so at a particular moment the electrons in an atom are more likely to be more on one side than the other, creating a temporary dipole
This dipole can then create another temporary (INDUCED) dipole (as higher electron density repulses the other electrons), which are then attracted to each other
Chain affect occurs
Which factors increase induced dipole- dipole interactions?
Larger molecules have more electons meaning stronger induced dipole-dipole interactions
So does larger exposed surface area has have bigger exposed electron cloud
Which molecules can form permanent dipole-dipole interactions?
Polar molecules (Delta positive of one molecule attracted to the delta negative of another)
When can hydrogen bonding occur and what does it do to melting and boiling points and other property?
If hydrogen is bonded to fluorine, oxygen or nitrogen
Massively increases them
Soluble in water
Why do simple covalent compouds have low melting and boiling points?
Weak intermolecular forces
Why don’t simple covalent compounds conduct electricity?
The overall covalent molecules are uncharged so they can’t cinduct electricity
What happens to the covalent bond when you melt or boil a simple covalent compound?
Nothing, only the intermolecular forces are affected
