Science Homework Help

I’m studying for my Biology class and don’t understand how to answer this. Can you help me study?

2.1

1. List the elements that make up the bulk of a human.
2. Explain the difference between essential elements and trace elements.
3. In humans iron is a trace element (needed for function of hemoglobin in red blood cells), explain what could occur if a human has iron deficiency.

2.2

1. What is the mass number and atomic number for carbon?
2. How many protons, neutrons, and electrons does carbon have?
3. What is an isotope?
4. The follwoing are isotopes of N: nitrogen-14, nitrogen-15, nitrogen-16. Provide the neutron # for each isotope.
5. How many valence electrons are in carbon? Oxygen?

2.3

1. Create a T-chart to compare polar covalent bonds vs. nonpolar covalent bonds. Make sure to include examples of molecules with each types of bond too.
2. Ionic bonds occur between atoms that do not share electrons equally. In an ionic bond, what is the charge of the anion? Cation?

2.4

1. Draw the Lewis dot structure of CH4 (methane). You may need to draw it on paper and upload the picture to your Word document.