Question

can someone help me with these chem questions ? thanks
Which statement describes the trend in first ionization energy for elements on the periodic table?

It generally decreases down a group because valence electrons are farther from the nucleus.
It generally decreases across a period because effective nuclear charge decreases.
It generally increases down a group because valence electrons are farther from the nucleus.
It generally increases across a period because effective nuclear charge decreases.

Answer 1

Going across a period on the periodic table we're adding a proton, so Zeff goes up as well as electronegativity. As electronegativity goes up across a period, it becomes harder for you to remove an electron as we go L/R. some exceptions to this are the transition metals.

from my understanding, as you go down a group what's happening is that you're increasing the number of shells in your atoms, i.e atomic radius gets bigger but now the valence electrons become farther from the nucleus and the pull of the nucleus is not as effective so as you go down a group it becomes easier to remove electrons, i.e. valence electrons are farther from nucleus. so i would say the ionization energy decreases down a group.

Answer 2

@Photon336 so whats the answer a,b,c or d?

Answer 3

a. It generally decreases down a group because valence electrons are farther from the nucleus.

Answer 4

thanks :) can you answer another one?

Answer 5

long story short valence electrons farther from nucleus so easier remove

Answer 6

yeah sure

Answer 7

What is the trend in electronegativity for elements on the periodic table?

It decreases across a period and increases down a group.
It decreases across a period and decreases down a group.
It increases across a period and increases down a group.
It increases across a period and decreases down a group.

Answer 8

@Photon336

Answer 9

increases across a period and decreases down a group.

Answer 10

@jammy987 do you know why?

Answer 11

yea thanks

Answer 12

can you answer another one? @Photon336

Answer 13

What is the trend in effective nuclear charge for elements on the periodic table?

It decreases across a period but is constant down a group.
It increases across a period but is constant down a group.
It is constant across a period but decreases down a group.
It is constant across a period but increases down a group.

Answer 14

it's definitely not constant across a period

Answer 15

so the answer would be @Photon336 ?

Answer 16

increases across a period but is constant down a group

Answer 17

last one How does the atomic radius change as you move down a group on the periodic table?

It decreases because additional valence electrons are farther from the nucleus.
It decreases because additional valence electrons experience more shielding.
It increases because additional valence electrons are farther from the nucleus.
It increases because additional valence electrons experience more shielding.

Answer 18

@Photon336

Answer 19

moving down a group... it definitely increases b/c additional valence electrons are farther from the nucleus

Answer 20

On the periodic table, the number of valence electrons in atoms increases left to right across a period. What effect does this have on the ionic radii of the elements?

It decreases across cations and decreases across anions.

It decreases across cations and increases across anions.

It increases across cations and decreases across anions.

It increases across cations and increases across anions.

Answer 21

and thanks so much your a lifesaver ! @Photon336

Answer 22

yeah no problem! let me see that last one

Answer 23

On the periodic table, the number of valence electrons in atoms increases left to right across a period. What effect does this have on the ionic radii of the elements?

It decreases across cations and decreases across anions.

It decreases across cations and increases across anions.

It increases across cations and decreases across anions.

It increases across cations and increases across anions.

Answer 24

@Photon336

Answer 25

I think for that one it would be adding electrons so it should increase across anions, decrease cations..

Answer 26

it wasnt that @Photon336

Answer 27

which one? the last question?

Answer 28

oh crap it said ionic radii! i missed that

Answer 29

yea @Photon336

Answer 30

In general

A cation is positively charged, meaning that it is an atom that has lost an electron or electrons. The positive charge of the nucleus is thus distributed over a smaller number of electrons and electron-electron repulsion is decreased, meaning that the electrons are held more tightly and the atomic radius is smaller than in the normal neutral atom.

Anions, conversely, are negatively charged ions: atoms that have gained electrons. In anions, electron-electron repulsion increases and the positive charge of the nucleus is distributed over a larger number of electrons. Anions have a greater atomic radius than the neutral atom from which they derive.

if you're adding electrons it should increase across both.. for this i'm not too sure.

Answer 31

let me know if that's correct

Answer 32

@jammy987

Answer 33

if that's not the right answer, I'll tag someone who may know

Answer 34

okay @Photon336

Answer 35

it wasnt right

Answer 36

@sweetburger can you help with this question:

On the periodic table, the number of valence electrons in atoms increases left to right across a period. What effect does this have on the ionic radii of the elements?

It decreases across cations and decreases across anions.

It decreases across cations and increases across anions.

It increases across cations and decreases across anions.

It increases across cations and increases across anions

Answer 37

It will decrease for cations as the atom loses an electron so the overall nuclear charge on the electrons becomes stronger causing a decreases in size. It will increase across anions as there is a gain of electron on the atom and therefore the effective nuclear charge is not as strong due to the extra electron shielding so the atomic radius decreases.

Answer 38

@sweetburger so the answer would be?

Answer 39

Was confused myself with this question lol.. I may have misinterpreted it.

Cation implies a stronger nuclear charge and smaller atomic radius. So it should decrease with cation..

But for an anion it gains an electron so that (but I was unsure because aren't we going across a period # of shells isn't increasing..)