Rank the following elements by electron affinity, from most positive to most negative ea value.
rank from most positive to most negative. to rank items as equivalent, overlap them.
argon, sodium, iodine, oxygen, phosphorus

Rank by electron affinity, from most positive to most negative : Argon - sodium-phosphorus-oxygen-iodine

Electron affinity indicates the energy released if an atom attracts electrons. The greater the energy released (negative value), the greater the tendency of the atom to attract electrons and become negative ions

In one group, electron affinity tends to decrease from top to bottom, whereas in one period, from left to right, affinity tends to increase

From the above statement, it can be concluded that the largest electron affinity (the most negative) is owned by the elements located on the upper right in the period system

Let see the position of elements in the periodic system

group VIIIA, noble gas

group 1A, alkali

VIIA group, halogen

VIA group

VA group

Then the location of the elements above from left to right according to the group are: sodium, phosphorus, oxygen, iodine and argon

Except for the alkaline (IIA) and noble gases(VIIIA), all major group elements have a negative electron affinity, with the halogen element having the greatest electron affinity

So the order from most positive to most negative:

Argon - sodium-phosphorus-oxygen-iodine

Existing data for afinity electrons from the elements above(kj/mole) :

Ar=Argon = 35

Na = sodium = -52.2

P = phosphorus = -72.4

O = Oxygen = -142.5

I = iodine = -298.4

the element would most likely have an electron affinity

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Ionization energy and electron affinity

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the trend in electron affinity

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Keywords: electron affinity, periodic system, atomic radius, metal, nonmetal

it is to be noted that an alpha particle is an helium nucleus. so it contains 2 protons 2 neutrons and has a mass number of 4. when alpha decay particles are ejected from the nucleus it gets transformed into an atom which has atomic number less than 2 and a mass number less than 4.

an equation that could represent alpha decay is radium 226 decay of alpha particle forms radon 222.

→

the answer for sodium is 0.186

the answer for rubidium is 0.251