General Chemistry Flashcards
What charge do protons have?
Positive
What charges do neutrons have?
No charge
What charges do electrons have
Negative
Whats the relationship between protons and electrons
Same number on periodic table eg carbon has 6 protons and neutrons
What are isotopes?
Same atomic number but different mass number
How do you calculate number of neutrons
Mass number - atomic number
What are the different orbitals
S, p, d, f
Finish the sentence, The closer the shell is to the nucleus …
Lower its energy
What are valence electrons
Electrons in outermost shell
Describe core electrons
Electrons in innermost shells
What is the aufbau principle
An electron goes into the atomic orbital with lowest energy so first 1s then 2s then 2p then 3s then 3p then 4s then 3d etc
Whats pauli exclusion principle
No more than two e- can be in an atomic orbital
Whats hunds rule?
An e- goes into and empty degenerate orbital rather than pairing up
When is an atom most stable
When it has 8 electrons or full outer shell
Describe lewis structure
Lewis structure is where dots and lines are used to represent valence electrons and bonds
When is a covalent bond formed
When e- are shared
Describe lone pairs
Valence Electrons that are do not form bonds
How many valence e- does Oxygen have and how many bonds do it form
6 valence electron and 2 covalent bonds
How many valence e does nitrogen have and how many bonds does it form
5 valence e and 3 covalent bonds
How many valence e does carbon have and how many bonds does it form
4 valence e and 4 covalent bonds
Explain electronegativity
Measure of ability of atom to pull e to itself
Describe a non polar covalent bond
Bonded atoms that have the same or similar electronegativities
Describe polar covalent bond
Bonded atoms have different electronegativites
Describe a dipole
Polar covalent bonds with negative and and positive end and a dipole moment
What are units for dipole
Debye
How do you calculate formal charge
No of valence electrons - (no of non bonded electrons + no of bonds)
What is a cation/ anion/ radical
+ charge = cation
- charge = anion
No charge = radical
Describe neutral H when bonded
1 bond and no lone pairs
Describe neutral c when bonded
4 bonds and no lone pairs
Describe neutral n when bonded
3 bonds and 1 lone pairs
Describe neutral o when bonded
2 bonds and 2 lone pairs
Describe neutral halogens when bonded
1 bond and 3 lone pairs
How does a sigma bond form
Head on overlap of atomic orbitals
What is a molecular orbital
Volume of space around a molecule where electron most likely to be found
How are orbitals conserved?
No of orbitals = no of molecular orbitals combined
What can an destructive overlap form
Sigma antibonding
How is a sigma covalent bond formed
Head on overlap of two atomic orbitals
What does a side to side overlap of p orbitals form
Pi covalent bonds
What does an out of phase overlap form
Pi* antibonding
(Different colours)
What does an in phase overlap cause
Pi bonding
(Same colour)
