Question

2.1 the nature of matter

1. the basic unit of matter is the
2. what is the center of the atom called?
3. what subatomic particles are found in the nucleus of an atom?
4. what subatomic particles have a negative charge?
5. identify the elements by its symbol:

c = h = na =

1. most of the mass of living things consist of 6 elements.

carbon, hydrogen, phosphorous, and

1. isotopes are atoms that have different numbers of
2. what makes an isotope radioactive?
3. what is a compound?

what example of a compound is provided in the text:

1. what element was used as a weapon in world war i?

chemical bonds

1. what type of bond is formed when electrons are transferred?
2. negatively or positively charged atoms are called:
3. when sodium and chlorine bond together, the sodium becomes negative / positive

the chlorine becomes negative / positive

1. what type of bond is formed when electrons are shared?
2. what is a covalent bond?
3. the structure that results when atoms are bonded together is called a:
4. what force explains how geckos can stick to walls?
5. (application)the molecule shown is methane.

it consists of one carbon bonded to four hydrogens.
it’s chemical symbol is: ch4
what type of bonds hold the elements in ch4 together?
explain how you know.

Explanation:

1. The basic unit of matter is the atom.
2. The center of the atom is the nucleus.
3. Protons and neutrons are in the nucleus.
4. Electrons have a negative charge.
5. C is carbon, H is hydrogen, Na is sodium.
6. The other elements are oxygen, nitrogen, sulfur.
7. Isotopes have different numbers of neutrons.
8. An isotope is radioactive when its nucleus is unstable.
9. A compound is a substance formed when two or more elements combine chemically. Example: water (could be a common example if not specified otherwise in text).
10. Chlorine was used as a weapon in WWI.
11. An ionic bond is formed when electrons are transferred.
12. Negatively or positively charged atoms are ions.
13. Sodium becomes positive, chlorine becomes negative when they bond.
14. A covalent bond is formed when electrons are shared.
15. A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms.
16. The structure when atoms are bonded together is a molecule.
17. Van - der - Waals forces explain how geckos can stick to walls.
18. Methane has covalent bonds. We know because carbon and hydrogen share electrons to achieve a stable electron configuration as shown by the electron - sharing in the structure.

Answer:

1. Atom
2. Nucleus
3. Protons and neutrons
4. Electrons
5. Carbon, Hydrogen, Sodium
6. Oxygen, Nitrogen, Sulfur
7. Neutrons
8. Unstable nucleus
9. A substance formed when two or more elements combine chemically; water (example)
10. Chlorine
11. Ionic bond
12. Ions
13. Positive; Negative
14. Covalent bond
15. A chemical bond that involves the sharing of electron pairs between atoms
16. Molecule
17. Van - der - Waals forces
18. Covalent bonds; Because carbon and hydrogen share electrons to achieve stable electron configurations as depicted in the structure.