Dmitri Mendeleev organized the chemical elements:
The elements in the present periodic table are arranged according to their:
A vertical column in the periodic table is called a:
A horizontal row in the periodic table is called a:
The majority of the elements in the periodic table are:
What does Bohr's theory state?
What is the capacity of the first electron shell?
Which of the following is the electron configuration for carbon:
Elements in the some group have:
Elements in the same period have:
Which element is classified as metalloid?
How many valence electrons does calcium have?
How many valence electrons does boron have?