Unit 3 Test Flashcards
Dalton
All elements are composed of atoms
Atoms of the same element are identical but different from other elements
Atoms can combine to form compounds in fixes ratios
Atoms rearrange during chemical reactions but are not created/destroyed
Thomson
Given credit for discovering electron
Found cathode ray is attracted by and charged plate
Measured the charge to mass ratio
Rutherford
Found atoms are mostly empty space
Found nucleus is small + charged, and in the center
Bohr
Changed rutherfords model to include newer discoveries about how the energy of an atom changes when it absorbs or emits light
Quantum
The difference between different energy levels
Which part of Dalton’s atomic theory are considered wrong today
Adams are not indivisible. They can be divided during nuclear reactions, causing them to form two smaller items,
Atomsare made of smaller, subatomic particle’s for example electrons neutrons and protons
Also not all Adams of the same element are identical. Isotopes have different number of neutrons
What happened in Thompson’s cathode ray tube experiment and how did he explain the results
The cathode rays were deflected by a positive charge plate or magnet. The rays were attracted to the positively charged plates, they were negatively charged (electrons)
What happened in Rutherford’s gold for oil experiment and how does he explain the results
The alpha particles mostly went through the gold for oil, indicating that Adams are mostly empty space. However the positively charged particles were occasionally deflected any way that indicates that the nucleus have a positive charge. That’s the nucleus is a small dense positively charged region in the center of Adams and Adams are mostly empty space
Please explain how a flame test experiment works. Use the term ground state electron excited state electron energy level and wavelength of light
When Adams are heated in the flame their electrons transition from the ground steaks excited state. When he excited state electrons return to the ground flame they give off light with a wavelength and energy corresponding to the size of the energy transition. Just depends on both excited state energy level and the ground state energy level of the electron
The orbital filling diagrams, explain how electron spin is important
When feeling an orbital with two electrons, the electrons must have opposite spins. He would show this with one of arrow and one down arrow
And the orbital filling diagrams explain how you applied Hunds rule
Huns rule states that you should have to fill all orbitals with a sub level for example 3P before paren up to electrons into a single orbital
Complete the table for the calcium ion
#of protons
#of electrons
Charge as an ion
20
18
2+
What is the atomic number
Number of protons per Adam
What is the mass number
Number of protons plus neutrons per Atom
Explain the law of constant composition and give an example
In samples of any chemical compound, the masses of the elements are always in the same proportions
Sample: H2O always contains 2 g of hydrogen for every 16 g of oxygen
How many formula units of sodium chloride are there in 3.241 g of NaCl
3.340×10 to the 22nd formula units of NaCl
Explain the law of multiple proportions and give an example
Whenever the same two elements form more than one compound, the different masses of one element that combined with the same mass of the other element are in the ratio of small whole numbers
Democritus
Among first to suggest atoms exist
Beloved atoms were indivisible and industractable
