4
the toothbrush became obsolescent when it had been used many times
What kinds of technology are we using today that are really obsolescent? Many of them will be gone within a few years.
Latin was one of the first languages. Many other languages have Latin roots. And Not all the elements have Latin names. Some are named after famous people and scientist. Such as Einsteinium.
There are 2 elements found in ammonium, nitrogen and hydrogen.
Many elements.
84 Elements
There are 118 elements found from Chemistry, not sure about other 2
The periodic table has about 118 elements, if that's what you're asking.
many
92
There are 4 elements in group-4.
how many atoms are in this compound