Lecture Four Flashcards
Draw in a table how an element can be represented with its full electronic configuration (EC), condensed ECa and its partial orbital diagram.
Draw the tool that can be used to predict how the sublevels will be filled in an atom.
What elements have exceptions to aufbau’s rule?
Cu and Cr.
Chromiums electronic configuration is [Ar] 4s1 3d5
Coppers electronic configuration is [ar] 4s1 3d10
Describe the relationship between orbital filling and the periodic table.
What do all elements in the same group have in common?
They have the same number of valance electron and thus similar chemical featrues.
What is the octet rule?
An atom is obeying the octet rule when it gains, loses or shares electrons such that the electronic configuration of the outer shell is consistent with ns^2np^6.
As the name suggests, eight electrons occupy the outer shell.
Atoms and ios existing with this electronic configuration in the outer shell are seen to exhibit extra stability.
This accounts for the stability observed for the group 8 noble gases.
The octet rule is also invoked to account for the stability provided by bonding molecules.
Define metallic radium?
Metallic radium: half the distance between adjaent nuclei in a crystal.
Define covaletn radius.
Covalent radium: half the distance between bonded nuclei in a molecule.
How does the atomic radium behave as you move down a group and accross a period?
n dominates within groups. Atomic radium generally increases in a group dfrom top to bottem, as the number of shells in the atom increase by increments of one.
Zeff dominates within periods. Atomic radium generally decreases in a period from left to right due to the increasing attraction of electrons to the nucleus.
Define ionisation energy.
The amount of energy required for the complete removal of one mol of electrons from one mol of gaseous atoms or ions; an energy-requiring process; value is positive in sign.
IE1 = first ionisation energy: removes outer most electron from the gaseous atom. Atom (g) –> ion^+(g) + e^-
IE2 = second ionisation energy
Atoms with lower IE1 tend to form cations (lose electrons) during reactions, wheresa those with a high IE1 (except noble gases) often form anions (gain electrons).
What is the relationship between ionisation energy and atomic size?
1) As size decreases, it takes more energy to remove an elecron. Since the electrons are closer to the positively charged nucleus, the electrostatis attraction requires more energy to overcome it.
2) Ionisation energy geerally decreases fown a group.
3) Ionisation generally increases across a period. As the number of protons in the culeus increases, the attractive fources on the electrons increases.
Explain successive ionisation energies.
Successive IEs increase, but a large increase is observed to remove the first core electron.
This is an indication of the stbility of a fully occupied shell.
Define electron affinity.
The charge accompanying the addition of 1 mol of electrons to 1 mol of gaseous atoms or ions.
Atom (g) + electron –> negative ion (g)
The amount of energy released when an electron is added to a neutral atom or molecule in the gaseous state to form a negative ion.[1]
Summeries IE and EA periodic trends.
1) Reactive non-metals:
Groups 16 and 17, in their ionic compounds they form negative ions (have high IEs and very negitive EAs).
2) Reactive metals:
Group 1, in their ionic compounds, they form positive ions (have low IEs and lightly negitive EAs).
3) Noble gases:
Group 18, they do not lose or gain electrons (have very high IEs and slightly positive EAs).
What are the angles between bonds in molecular geometries?
