<u>Answer:</u>
Carbon and silicon both are tetravalent elements as compared to germanium, tin, and lead which are divalent.
That's because Ge, tin, and Pb show inert pair effect and has a greater nuclear effective charge on the 's' electrons due to poor shielding effect. .That's why these elements are not able to share their valence electrons while carbon and silicon does and show "catenation" which is the ability to form long chain molecules.
Answer:- 
Solution:- It is a simple unit conversion problem. We could solve this using dimensional analysis.
We know that, 1 US dollar = 100 cents
1 cent = 1 US penny
So, 1 US dollar = 100 US pennies
Let's make the set up starting with 1 penny as:
=
Therefore, we can bye of Cf in one US penny.
Answer: 9.3 x 10^ 18 g CO
Explanation:
Start by knowing that carbon monoxide is the compound CO. To convert molecules to grams, you first need to convert molecules to moles. This can be done using the conversion factor for Avogadro's Number:
(2.0 x 10^5 molecules CO) x 1 mol CO / 6.02 x 10^23 molecules CO
This cancels molecules CO.
Then, you can convert moles to grams, which is your desired quantity. You can find the number of grams for CO by looking at the periodic table and adding together their masses. C = 12 g and O = 16 g. Total of 28 g CO:
(1 mol CO) x 28 g CO / 1 mol CO
This cancels mol CO, which leaves grams CO.
