Question

ch.6 worksheet #1 {50pts}
fill in the missing information into the empty boxes.
scientist john dalton j.j. thomson ernest rutherford niels bohr quantum model
atomic model (picture w/labels)
what did he \discover\?
describe his \experiment\

complete the following chart filling in the appropriate information about the atoms of the elements.
element atomic number mass number number of protons number of neutrons number of electrons isotopic notation
17
15 31
38 50
neon 20 10 9
79 116

Explanation:

Step1: Recall atomic - related concepts

Atomic number = number of protons. Mass number = number of protons + number of neutrons. In a neutral atom, number of protons = number of electrons. Isotopic notation is written as $_{Z}^{A}X$ where $Z$ is the atomic number and $A$ is the mass number and $X$ is the element symbol.

Step2: For the first row (atomic number = 17)

Atomic number = 17, so number of protons = 17. Mass number = 17, number of neutrons = mass number - number of protons = 17 - 17=0. Number of electrons = 17 (since neutral atom). Isotopic notation is $_{17}^{17}X$. But this is not a common isotope. Assuming it's a mis - write and if we consider chlorine ($Cl$) which has atomic number 17, a common isotope is $_{17}^{35}Cl$.

Step3: For the second row (atomic number = 15)

Atomic number = 15, so number of protons = 15. Mass number = 31, number of neutrons = 31 - 15 = 16. Number of electrons = 15. Isotopic notation is $_{15}^{31}P$ (since the element with atomic number 15 is phosphorus).

Step4: For the third row (mass number = 38, number of neutrons = 50)

This is incorrect as mass number (38) cannot be less than number of neutrons (50). Let's assume it's a mis - write. If we assume atomic number = 38 (strontium, $Sr$), mass number = number of protons+number of neutrons. If number of protons = 38, and assume correct mass number and neutrons values are swapped, if mass number = 50, number of neutrons = 50 - 38 = 12, number of electrons = 38. Isotopic notation is $_{38}^{50}Sr$.

Step5: For the fourth row (element = neon)

Atomic number of neon ($Ne$) is 10. Mass number = number of protons+number of neutrons = 10 + 10=20. Number of electrons = 10. Isotopic notation is $_{10}^{20}Ne$.

Step6: For the fifth row (number of protons = 79, number of neutrons = 116)

Atomic number = 79 (gold, $Au$). Mass number = 79+116 = 195. Number of electrons = 79. Isotopic notation is $_{79}^{195}Au$.

Answer:

Element	Atomic number	Mass number	Number of protons	Number of neutrons	Number of electrons	Isotopic notation
Phosphorus ($P$)	15	31	15	16	15	$_{15}^{31}P$
Strontium ($Sr$)	38	50	38	12	38	$_{38}^{50}Sr$
Neon ($Ne$)	10	20	10	10	10	$_{10}^{20}Ne$
Gold ($Au$)	79	195	79	116	79	$_{79}^{195}Au$

For the top part about scientists:

• John Dalton:
• Atomic model: Solid - sphere model.
• Discovery: Atoms are the smallest indivisible particles of matter.
• Experiment: Based on laws of multiple and definite proportions from chemical reactions.
• J.J. Thomson:
• Atomic model: Plum - pudding model.
• Discovery: Electron.
• Experiment: Cathode - ray tube experiment.
• Ernest Rutherford:
• Atomic model: Nuclear model.
• Discovery: Atomic nucleus.
• Experiment: Gold - foil experiment.
• Niels Bohr:
• Atomic model: Bohr model.
• Discovery: Quantized electron orbits.
• Experiment: Based on emission and absorption spectra of hydrogen.
• Quantum model:
• Atomic model: Quantum mechanical model.
• Discovery: Wave - particle duality of electrons, probability distribution of electrons.
• Experiment: Many experiments such as the double - slit experiment for electrons, Stern - Gerlach experiment etc.