Question

1. How many valance electrons are in the following elements?

Hydrogen:

Helium:

Lithium:

Carbon:

Oxygen:

Chlorine:

Sodium:

2) Why is it necessary to understand the number of valance electrons on an element?



3. Explain why CH4 is one of the most common molecules found in nature. Are the bonds between the atoms ionic or covalent?



4. Explain how buffers help the human body to maintain homeostasis. What is one of the most important buffered fluids in the body? Why?

Answer 1

Answer:

Hydrogen: 2

Helium: 2

Lithium: 3

Carbon: 6

Oxygen: 8

Chlorine: 7

Sodium: 1

Ans 2: Valence electrons are quite important. They are the electrons that exist in the outermost shell/cloud of an atom at the highest energy level. When atoms interact chemically through bonding, it's their outer shell electrons that are involved. The number of outer shell or valence electrons influences

Ans 3: the cross represents the electrons of methane whereas dots represent the electrons of hydrogen.  

Carbon shares total 4 electrons, 1 with each hydrogen and all 4 hydrogen share their 1 electron each with carbon. Hence, covalent bonding is present in the methane molecule.

Ans 4: The body's chemical buffer system consists of three individual buffers out of which the carbonic acid bicarbonate buffer is the most important.  

Cellular respiration produces carbon dioxide as a waste product. This is immediately converted to bicarbonate ion in the blood. On reaching the lungs it is again converted to and released as carbon dioxide.

While in the blood , it neutralizes acids released due to other metabolic processes. In the stomach and duodenum it also neutralizes gastric acids and stabilizes the intra cellular pH of epithelial cells by the secretions of bicarbonate ions into the gastric mucosa.

;