On the Subject of Periodic Words

Remember that game we all used to play when we were bored in chemistry class? Now, that game is on a bomb.

Presented is a display with a word on it, an initially blank display below it, a numbered keypad, and a stage counter.

The displayed word can be represented using symbols in the Periodic Table of the Elements. For three stages, input the atomic numbers of the word’s constituent elements — concatenated in order — prepending zeroes to each number until they are all of length three.

Note that a word may have multiple solutions. In this case, any solution which forms the word given will be accepted.