The modern Icelandic alphabet has 32 letters, but C, Q, W, and Z don’t exist in it. Those sounds simply aren't native to the language. Good luck spelling “quiz” in Icelandic!
The Icelandic alphabet is based on the Latin alphabet, but it includes some unique letters and excludes a few.
Here’s the full Icelandic alphabet:
A Á B D Ð E É F G H I Í J K L M N
O Ó P R S T U Ú V X Y Ý Þ Æ Ö
That’s 32 letters total.
Á, É, Í, Ó, Ú, Ý – considered separate letters, not just accented versions
Þ (thorn)... pronounced like the “th” in "thing", it’s a Viking classic
Ð (eth)... like the “th” in "this"... softer and voiced
Æ... sounds like the "i" in "ice"
Ö... sounds sort of like the “u” in “fur” but rounder.
Icelandic does NOT use: C - Q - W - Z
Those only appear in foreign names and loanwords.