Most likely "lap".
dog
cur
cur
dog cow mop cot
tar, gob
Idk words, numbers and a bunch of other stuff isnt made up of matter so there really are no elements in the word dog.
That is a riddle. The answer is "alphabet". It has three syllables, al-pha-bet, and the alphabet contains 26 letters.
Dog rewards are often called, "Treats", which is a 6-letter word.
An Australian dog that is also a five-letter word is a Dingo.
emu eel cat dog rat pig cow sow doe
dog
tar, gob