Respuesta :
Answer is: C. They showed Mendeleev’s predictions were correct.
Dmitri Mendeleev published a periodic table of the chemical elements in 1869.
Mendeleev noted gaps in the table and predicted then undiscovered elements existed eka-silicon (germanium) and eka-boron (scandium).
For example, germanium discovered in 1886 and it had proporties as Mendeleev predicted.
There are 118 unique substances (elements) arranged on an amazing chart that reveals their hidden secrets to anyone who knows how to read it.
The first chemical element is hydrogen (atomic number is 1) and the last is oganesson (atomic number is 118).
Elements are scheduled in periodic table, ordered by their atomic number.
They showed Mendeleev’s predictions were correct........ is the answer