We’d already had an Ifor Listener this year with Death Row back in February. That had Lizzie Borden taking an axe to her parents. Before that, we had a different form of dismemberment when Ifor presented us with the Russian Matryoshka dolls.

This week, all across clues and twelve downs lost a word each. Knowing how Ifor likes to dismember words by removing letters, I wondered if the words to be removed could be parts of other words. Without giving too much away, it soon became clear that that was unlikely. The removed words would give the wordplay to seven answers “from which a thematic set of answers nominally derive”. The endgame would require a bit of jiggery-pokery by the look of it.

I was off to a flying start with 1ac AGNATE, 5 EMERSE, 2, ICTAL, 16 ARUM and 17 ANIONIC. With that many acrosses, it seemed churlish not to try the down clues, and 1 ACHAR, 3 ARAMAIC, 4 TAMES, 7 ECHO and 8 SALIAN, although that last one needed to be verified in Chambers.

10ac Coagulated part within brittle dried fruit (7) took a bit of time to unravel despite appearing to be CURRANT from the letters already in the grid. Chambers has a huge list of meanings for run, but near the end of the vts was “coagulate”. The CURT bit needed a back reference with “curt” appearing under brittle, but not the other way round.

Another tricky clue (for me) was 13ac Ditch secret, issuing it shifts heartaches (4). Again, the answer was obviously HA-HA, but it needed the extra word issuing to be removed to see that it was a compound anagram (SECRET + HA-HA = HEARTACHES*).

The top left quadrant of the grid came together nicely, and I basically worked my way down slowly filling in the entries. The grid turned out to be only marginally more difficult than the average for an Ifor puzzle.

So what did we have to do next. Well, the wordplay clues gave the following:

• Every second part from issuing — SUN;
• Mine water shows — NEW;
• Invite out keeping advanced command paper — INACTIVE (that one took a bit of time): INVITE* around (A + C);
• Hotel nut died erroneously — HIDDEN;
• Inside more marked orienteer’s originally becoming absent — STRANGER [STRONGER with A for O(rienteer)];
• Fearful Scottish institute united mass — RADIUM;
• One’s sun again red — OGANESSIAN (well that anagram didn’t exactly leap off the page!! with red being the anagram indicator).

Obviously (from the above comment), Oganessian was the last to be solved, but it was when I got RADIUM that I knew we were in chemical country. A lot came together here reasonably quickly for me. The word that would probably need replacing was INERT, although I needed Wiki to remind me that the inert gases are now called NOBLE and this was confirmed by Chambers. The seven such elements were:

• Helium (He, atomic number 2), derived from the Greek sun, Helios;
• Neon (Ne, 10), from the Greek “new”;
• Argon (Ar, 18), from the Greek for “inactive”;
• Krypton (Kr, 36), from the Greek for Superman “hidden”;
• Xenon (Xe, 54), from the Greek for “stranger”;
• Radon (Rn, 86), all tied up with Radium (?);
• Oganesson (Og, 118), named after a Russian physicist Yuri O, ie Oganessian.

All that was left now was to find where those elements could fit into words already in the grid. Some of these were easy to decipher, some less so! They were GU-RN-ARDS, BAN-K R-ATE, TA-XE-MES, GAMB-OG-IAN, MILIT-AR-IA, SA-HE-LIAN and PHO-NE-TIC. Joining up these points in the grid gave 18, the group number for the right-hand column in the periodic table where they all sit, hence this puzzle’s title.

Blimey, guv!! Ifor puzzles always have a lot of thematic material, and this was no exception. Thanks.