All Questions
Tagged with periodic-trends atoms
13
questions
3
votes
3
answers
7k
views
Which atom is the smallest atom?
Is hydrogen or helium the smallest atom? My teacher said that the smallest atom is the helium atom, but I think that the smallest atom is the hydrogen atom. It has a single electron and a single ...
user100905
1
vote
1
answer
2k
views
Trend in atomic volume across a period [closed]
"Atomic volume decreases along a period, reaches a minimum at the middle, and then increases for the rest of the period"
Why does the atomic volume, along a period, initially decrease, ...
- 431
1
vote
0
answers
295
views
Why doesn't core charge increase down a group? [closed]
Atomic radius increases down a group because the electrons feel a lesser attraction to the positive nucleus (due to shielding from inner shells). Why then, doesn't core charge decrease seeing as core ...
- 151
3
votes
2
answers
3k
views
What is the true depiction of the periodic table?
Normally with the periodic table the lanthanide series is separated out because it's long and would make the table wide. I looked for an expanded version and found this:
I found it kind of strange ...
- 195
2
votes
0
answers
266
views
Comparision of the Ionisation Energy Change of the alkali metals and noble gases?
Currently I compare the ionisation energys of the alkali metals:
Li: $\pu{0.52 eV}$
Na: $\pu{0.50 eV}$
K: $\pu{0.42 eV}$
Where only a slight drop (appr. remain constant) occurs.
This ionisation ...
- 411
11
votes
1
answer
11k
views
Why does cobalt have a higher atomic mass than nickel?
I understand that this deviation from the general trend of increasing atomic number and atomic mass is because cobalt's isotopes tend to have more neutrons than nickel's. Why is that the case? How ...
- 245
1
vote
1
answer
383
views
Why does ionization increase from Li to Be? [duplicate]
If ionization energy decreases from $\ce{N}$ to $\ce{O}$ due to the pairing of electrons (causing electric repulsion and greater potential energy) in the $\mathrm{2p}$ orbital in the $\ce{O}$ atom, ...
- 1,529
1
vote
2
answers
4k
views
Periodic Trends of Zeff and Electronegativity
The effective nuclear charge $Z_\mathrm{eff}$ increases from left to right and from top to bottom. Can you explain why it increases from top to bottom?
Also can we explain the periodic trend of ...
- 11
5
votes
3
answers
45k
views
Why does ionization energy increase as we go from left to right in a period?
Why does ionization energy increase as we go from left to right in a period?
In my textbook, the explanation is as follows:
"This is consistent with the idea that electrons added in the same ...
- 415
3
votes
1
answer
216
views
Can you calculate the properties of a substance based solely on its atomic properties?
I'm trying to write some software that I can use to determine, roughly, what the physical properties of a pure substance are. I know I could just use a database of the known properties of each element,...
- 153
4
votes
2
answers
5k
views
Atomic radii of Sc, Ti, Fe, and Co
The atomic radius of Sc is $\pu{162pm}$, Ti is $\pu{147pm}$, $\ce{Fe}$ is $\pu{126pm}$, and that of $\ce{Co}$ is $\pu{125pm}$.
The electronic configuration of $\ce{Fe}$ is $\ce{[Ar] 3d^6 4s^2}$, and ...
- 1,380
35
votes
1
answer
12k
views
Why are there two Hydrogen atoms on some periodic tables?
Most periodic tables only feature one Hydrogen atom, on the top of the first group. But some, like the one I was given, also show Hydrogen in the 7th group, to left of Helium.
Why are there two ...
- 1,105
37
votes
3
answers
47k
views
Why do atoms generally become smaller as one moves left to right across a period?
It seems to me that the addition of electrons and protons as you move across a period would cause an atom to become larger. However, I'm told it gets smaller. Why is this?
- 827