The Atom - Shodor
What is an Atom?
Data collected from selected atoms.
|[pic] |Electron (-) |
| | |
| |Proton (+) |
| | |
| |Neutron (neutral) |
1 amu = 1.6606 x 10-24 g
[pic]
A is the mass number
Z is the atomic number
[pic]
The nucleus of an atom contains the protons and the neutrons.
1H and 2H are isotopes of hydrogen.
12C and 13C are isotopes of carbon.
An ion is a charged particle, O2- and Na+ are ions.
You can’t see all the neutron and protons in the nucleus in the diagrams
Chemists identify isotopes by using a mass spectrometer. The separation is possible because each isotope has a different mass. Lighter masses will bend more as they pass through the magnet field.
[pic]
Critical Thinking Questions
1. How many protons are found in 12C?_______ 13C? ____13C- ?____
2. How many neutrons are founds in 12C?_____ 13C? ____13C- ?____
3. How many electrons are found in 12C?____ 13C?_____ 13C- ?____
4. Based on the data presented above,
a. What do all carbon atoms (and ions) have in common?
b. What do all hydrogen atoms (and ions) have in common?
5. What is the significance of the atomic number, Z? Where will you find it on the periodic table?
6. Look at a periodic table, what do all nickel (Ni) atoms have in common?
7. How is the mass number, A, determined?
8. What structural feature is different in isotopes of a particular element?
9. What feature distinguishes a neutral atom from an ion?
10. Where is most of the mass of an atom, within the nucleus or outside of the nucleus? Explain your reasoning.
11. Complete the chart below:
|Isotope |Atomic Number |Mass Number |Number of Electrons |
| |Z |A | |
|31P |15 | | |
|18O | | |8 |
| |19 |39 |18 |
|58Ni2+ | |58 | |
12. What is the mass (in grams) of
a. one 1H atom? ______________
b. one 12C atom? _____________
13. What is the mass (in grams) of 4.35 x 106 atoms of 12C?
14. What is the mass (in grams) of one molecule of carbon dioxide which has one 12C atom and two 16O atoms?
15. Define mass number
16. Define atomic number.
17. How many electrons, protons, and neutrons are found in each of the following?
|Atom or ion |Electrons |Protons |neutrons |
|24Mg | | | |
|23Na+ | | | |
|35Cl | | | |
|35Cl- | | | |
|56Fe3+ | | | |
|15N | | | |
|16O2- | | | |
|27Al3+ | | | |
18. Estimate the mass of one 14C atoms (in amu) as precisely as you can from the data given here. Explain your answer.
19. Use the data given to estimate the values (in amu) of
a. An electron
b. A proton
c. A neutron
20. The mass values calculated in #18 are only approximate because when atoms (up through iron) are made (mainly in stars) from protons, neutrons, and electrons, energy is released. Einstein’s equation E = mc2 enables us to relate the energy released to the mass loss in the formation of atoms. Use the known values for the mass of a proton, 1.0073 amu, mass of a neutron, 1.0087, and the mass of an electron, 5.486 x 10-4 amu, to show that the mass of a 12C atom is less than the sum of the masses of the constituent particles.
Summary of Activity: Describe an atom.
................
................
In order to avoid copyright disputes, this page is only a partial summary.
To fulfill the demand for quickly locating and searching documents.
It is intelligent file search solution for home and business.