CHEMISTRY COMMUNITY

does electron affinity measure the energy required to gain an electron or the attraction to an electron? for example an element far right on the periodic table would hav a high nuclear charge, and it would be easy to add an electron. does this mean the electron affinity is high (because the attraction is high) or it is low (the energy required to add the electron is low)

The electron's affinity measures the energy given off when one mole of atoms in the gaseous state each takes in one (or more) electrons to become a mole of anions in the gaseous state, or basically the energy required to gain an electron to become an anion.
That being said, the nuclear charge of an electron measures the pull that the nucleus has on these electrons (positive & negative charge), and relates to the increase in atomic number - which is an increase in the protons in the nucleus that attracts electrons more. When you go across a period of the periodic table, atomic number increases, but electrons are being added to the same energy level.
This means that an incoming electron will be more attracted to the nucleus, which implies that the energy gain when it is added to the atom will be more significant
therefore,
electron affinity increases.

Electron affinity is the energy released when an electron is added, so it makes sense when we think about its trend on the periodic table. The energy released when an electron is added increases across a period because elements are always trying to reach the most stable configuration. They want to be like the cool kids, or Noble gases, and that is why energy is released when you add an electron to something like Fluorine and cause it to reach that much more stable and lower energy state. It makes sense that little energy would be released to an element like Sodium, since it wants to lose an electron really badly and instead gets an electron.

I believe electron affinity is the amount of energy released or used when an electron is added to an atom.

The way a UA described it to me was that electronegativity is the ability of a neutral atom to attract electrons towards itself and electron affinity is the energy released when the electron is added to the neutral atom (kind of like a cause and effect I think) hope this helps

Electron affinity is the amount of energy released when an electron is gained. Another way of saying this would be how bad the element wants to gain an electron.

Can someone explain the difference between electron affinity and electron negativity again? I understand that both properties have the same periodic trend. Is there an easier way that I can remember the difference?

electron affinity is an energy. Electronegativity is a relative scale

A lower electron affinity indicates that an atom does not accept electrons as easily.

Fluorine is the most electronegative

Electronegativity represents how much the atom "wants" an electron. Electron affinity is a specific measurement of the energy released when adding an electron.

Electron affinity is the energy released when an electron is added to a neutral atom in order to form a negative ion. Electron affinity increases as you go up the periodic table and from left to right to the periodic table. This is because the electrons added to the energy levels get closer to the nucleus.

If electron affinity is negative then does that mean that the atom accepts electron easily and vice-versa meaning if electron affinity is positive the atom has difficulty accepting an electron?

As a side note, the general trend for electron affinity is that it increase upwards and from left to right of the periodic table.

Atoms with low electron affinity (i.e. alkali metals) lose electrons far more easily to have a full valence shell whereas it is far easier for a halogen (say Fluorine) to pick up an electron and fill its valence shell. Thus, we say halogens have a high electron affinity.

Florine is the most electronegative atom, using that fact you can establish a variety of periodic trends from the table, as you move from left to right on a period all subshells become smaller ever so slightly due to the increase in protons, and as you move from top to bottom the radius increases by an entire subshell, so we can establish fluorine also has the highest ratio for protons to radius making it the most electronegative