A Greek philosopher
He was one of the first to ____ about an atom’s e______
Believed that matter was composed of tiny invisible particles called a____
He had no experimental e______ thoughts
Who am I? Year ____ B.C.
Think, existence, atoms, evidence, Democritus, 400
A meteorologist
Unlike Democritus, I had experimental e________ to support my theory.
I had 4 major points (p______) to my t______
Who am I? Year (17__-18____)
Evidence, postulates, theory, John Dalton, 1766, 1844
John Dalton’s postulates (t or f)
1. All elements are made of atoms which are indivisible
2. Atoms of the same element are identical. Atom’s of different elements are different. Atoms of different elements are different
3. Atoms of different elements mix or combine in a whole # Ratio
4. Chemical reactions occur when atoms separate, join, or rearrange. In chemical reaction, atoms of one element never change into another
- False; atoms are not indivisible
- Mostly true; However, they are not always identical because they can differ in the number of neutrons (forming isotopes) or in their energy states (like speed or rotation)
- True; but with a crucial clarification from Dalton’s atomic theory: atoms of different elements chemically combine in simple whole-number ratios to form compounds
- The first part of the statement is true, as chemical reactions involve atoms separating, joining, or rearranging to form new substances. However, the second part is false: in typical chemical reactions, atoms of one element do not change into another element; rather, they rearrange to form new compounds.
I, .. _____, did C___ ray tube experiment. In the tube was an ____ gas and two plates a ___ and negative. The particles in the gas were attracted to the ____ plate. Therefore particles must have negative charge.
Ratio is all same for all atoms except/m => e- is universally in all atoms i_____) 1859-19____
Discovered e____
From his experimental evidence he believed that atoms was a solid ____ sphere with electrons shoved into the side of it.
His model was called “___ _____ model”
J.J. Thomson, Cathode, inert, positive, identical, 40, electron, positive, plum, pudding
___ ____ford did ____ foil experiment (_____ model,) used ____ foil
Ernest Rutherford, gold, nuclear, gold
The experimental setup for the ____ ___ experiment was that a r_____active that emitted a___ particles was directed toward a then sheet of ___ ____ that was surrounded by a screen which would allow detection of the ___ particles
Gold foil, radioactive, alpha, gold foil, deflected
According to the ____ _____ model all the a____ particles should have passed through the gold foil with little or no deflection. Rutherford found that a small percentage of a___ particles were d_____ at large a____, which could be explained by an atom with a very small, dense, positively-charged nucleus at its center
Plum pudding, alpha x2, deflected, angle
I arranged elements per atomic mass problem 1. Some gals: elements later discovered (properties _____) 2. Elements properties sometimes liked up better was switched
Who am I? (18___)
Mendeleev 1869
I arranged elements/ atomic numbers
_____ law: when elements are arranged in order of increasing atomic numbers there is periodic repetition of their ____ and ____ properties
Period: horizontal rows (1-___)
Group: vertical column 1-___
Who am I? (19____
Periodic, physical, chemical, 7, 18, Mosley,1913
Statement that when the elements are arranged by increasing atomic number there is a periodic repetition of their chemical and physical properties
Periodic law
Group 1,2,13-18 elements
Representative elements
Group 3-12 elements
Transition elements
Group 1 element ( except H)
Alkali metals
Group 2 elements
Alkaline earth metals
Group 17 elements
Halogens
Group 18 elements
Noble gases
Atoms or bonded group of atoms that has a positive or negative charge
Ion
Energy required to remove an electron
Ionization energy
Statement that atoms tend to gain, lose, or share electrons to acquire a full set of eight valence electrons
Octet rule
Indication of an Atom’s ability to attract electrons in a chemical bond
Electrons gravity
Electrons in outermost energy level (electron shells)
Valence electrons
Valence electrons
Group 1:
2:
13:
14:
15:
16:
17:
18:
1,2,3,4,5,6,7,8
Group 1:
2:
13:
14:
15
16:
17:
+1, +2, +3, +-4, -3, -2, -1
Statement that aims tends to gains, lose, or shade electrons to acquire a full set of eight valence electrons
Octet rule
