Chemistry unit 6 Flashcards
What direction is a period?
The horizontal (left to right)
What direction is a group/family
Vertical
What is atomic radius/ Atomic Radii
The total distance from the nucleus of an atom to its outermost orbital
What is the pattern of Atomic Radius?
It decreases from left to right (due to increased charge on the nucleus)
It increases from top to bottom in a family (due to the shielding effect and larger orbitals)
What is electronegativity
Electronegativity is a measure of how strongly an atom attracts a bonding pair of electrons .
What is the electronegativity trend
It increases from left to right
It decreases from top to bottom
What is ionization energy
It is the energy needed to remove an electron from a neutral atom
What is the ionization energy trend?
It increases from left to right (period)
It decreases from top to bottom (family)
What is the difference between the 1st and 2nd ionization energy
The 1st is the energy needed to remove the first electron from a neutral atom.
The 2nd is the energy needed to remove the second electron. *(and so forth)
Why does the difference between 1st and 2nd ionization energy vary so much?
The 2nd ionization energy is always gonna be larger because it requires more alot more energy to remove an electron from a cation than from a neutral atom.
What is electron affinity?
Electron affinity is how badly a neutral atom wants to gain electrons.
What is the electron affinity trend?
It increases from left to right
It decreases from top to bottom
What is shielding?
Shielding is when the inner electrons act as a shield that prevents outer electrons from feeling an effective nuclear charge.
What are intramolecular forces?
Forces within a molecule or ionic compound that keep the molecule together.
Ex. Bonds between atoms
What are intermolecular forces?
The attraction between molecules or ions and molecules. IN A SOLID OR LIQUID STATE.
They determine many of the physical properties of a substance.
Which is stronger Intramolecular or Intermolecular?
Intramolecular - strong
Intermolecular - weak
What do atoms valence shells want
They want to achieve a full valence shell
For ionic bonding how does the electron configuration change?
The arrow from the atom that is loosing an electron must go to the atom that is gaining an electron
In covalent bonding how does the electron configuration change?
The two arrows come together in the middle to show that they are sharing.
What is a polar covalent bond?
It is when electrons are shared unequally between two atoms.
When does polar covalent sharing occur?
When the electronegativity difference is between 0.5 and 1.7 *(or 2.0 if it is only non metals)
What does polar covalent sharing result in?
Dipoles
What are dipoles?
It is when a molecule has a partially positive and a partially negative end (poles).
What are the steps for drawing Lewis diagrams for simple molecules?
Step1: Count valence E-
Step2: Determine the central atom.
Step3: Draw single bonds to the central atom.
Step4: Place remaining e- as lone pairs.
Step5: Turn lone pairs into double or triple bonds to give every atom a full valence shell.
Step6: Check period 3 or higher central atoms for a formal charge of 0.
When writing Lewis diagrams for ionic compounds how should they be arranged?
Brackets around dot structure with the charge next to them
negative next to positive.
How to represent the dipoles in lewis structures
By using an arrow with a plus on one end
The + represents the slightly more positive pole and the arrow represents the slightly more negative.
What does adding an electron (anion) do to the ionic radius?
Makes the atom bigger.
What does taking away an electron (cation) do to the ionic radius?
Makes the atom smaller.
What are the three elements that have an exception to the octet rule?
Be, B, and Al.
How many electrons does Be need to be satisfied?
Only 4.
How many electrons does B need to be satisfied?
Only 6.