Which groups on the periodic table contain metalloids?
a. groups 1–2
b. groups 3–12
c. groups 13–16
d. groups 17–18

Groups 13-16.

Explanation:

There are 18 groups in the periodic table.

The first and second group contains only metal (alkali and alkaline earth metals)

The third to twelfth group (3-12) also contains only metals (the transition metals and inner transition metals).

Now the groups from 13 to 18 contains metals, non metals and metalloids

group 17-18 are strictly non metals

Thus the metalloids find their place in groups 13-16.

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"