# Single letter chemical elements on a 2x2 grid

In the past somebody showed me the puzzle below. I remember the answer but not the entire solution. Here it goes:

On a grid of 2x2 put four single letter chemical elements. The result should have two letter elements on the horizontal, vertical and diagonal.

• So, what exactly is the question??
– Sid
Commented Aug 3, 2016 at 15:34
• Well I thought there should be a element in every direction. So ltr and rtl. By now I know that's impossible. What frustrated me is that there are two possibilities depending on the direction you read the diagonal. Commented Aug 3, 2016 at 16:17

First row:

S N

Second row:

B I

The elements are:

Sn - Tin, Bi - Bismuth, Sb - Antimony, Ni - Nickel, Si - Silicon, Nb - Niobium

• I've just deleted my comment cause you spotted the diagonals :) Commented Aug 3, 2016 at 15:38
• +1 I saw the answer for the diagonal from upper left to lower right, but did not consider the one from lower left to upper right.
– Herb
Commented Aug 3, 2016 at 15:40
• How is this not accepted and the other, later one is accepted? Commented Aug 3, 2016 at 19:01
• @ΈρικΚωνσταντόπουλος both answers are correct if you reverse the reading direction of the diagonal. To me left-to-right seems more logical than top-to-bottem. Although 11 people disagree. Is there a rule of thumb when reading diagonally? I can't find anything about it on the web. Commented Aug 3, 2016 at 20:12

Taking a quick look at a period chart, the only valid answer, giving your hint is:

SB
NI

for

Antimony (Sb)
Tin (Sn)
Silicon (Si) Nickel (Ni)
Bismuth (Bi)

• @PeterJanssen There is no element with the symbol Bn Commented Aug 3, 2016 at 15:49
• It seems that there is consensus about what direction a diagonal needs to be read. Commented Aug 3, 2016 at 16:19
• Nb is niobium, which isn't explicitly listed in the elements above. Commented Aug 3, 2016 at 18:59
• How do you know this is the only answer? (The search space is pretty small, so I suppose exhaustive search would be trivial) Commented Aug 3, 2016 at 22:47
• The original question had the letters I, s, b, and n in the hint.
– Herb
Commented Aug 3, 2016 at 23:27

+-+-+
|S|N|
+-+-+
|I|B|
+-+-+

S: Sulfur
Si: Silicon
Sb: Antimony
Sn: Tin
I: Iodine
In: Indium
N: Nitrogen
Ni: Nickel
Nb: Niobium
B: Boron
Bi: Bismuth

--------------------------------------------------------------------------------

Row entries: 2
Column entries: 2
Total entries: 4
Other entries: [CHEM_EL] 11 [CHEM_EL_L2] 7
Total: 15
Other tallies: [DUPE] 0

First row:

SC

Second row:

NO

And the elements are:

Scandium (Sc), Cesium (Cs), Nobelium (No), Tin (Sn), Cobalt (Co), Copernicium (CN -diagonal), Osmium (Os - diagonal)

• Kudos for using Cn. Wasn't named when I first heard about this puzzle. Commented Aug 4, 2016 at 19:11

• Welcome to Puzzling.SE! Please double-check the question contents and your answer to see if it is correct. Here, the elements Ci and Ic are specified, but they do not exist. Commented Aug 3, 2016 at 19:03