Chemistry Flashcards
What did democritus discover
the atom
Democritus experiment that was used/What was proposed
matter could not be divided into smaller pieces
Democritus additional information
Greek philosopher who named the atom after greek root “atomos” meaning indivisible
Dalton what did they discover?
Atomic Theory
Dalton Experiment that was used/What was proposed
4 postulate Atom was smallest representation of element Element is only 1 atom Compound is 2 or more When bonding atoms dont change
Dalton Additional information
viewed the atom as solid tiny balls and English Teacher
Thomson What did they discover?
Discovered Electron
Thomson Experiment that was used/What was proposed
Used gas filled tubes, electricity, and magnets
Thomson Additional information
viewed the atom like plum pudding or raisin bread - positive dough and negative raisins (electrons)
Rutherford What did they discover?
Discovered Proton and Nucleus
Rutherford Experiment that was used/What was proposed
Fired Particles at gold foil and noticed the reflection of particles
Rutherford Additional information
discovered that atom was mostly empty space
Bohr What did they discover?
Discovered Electron Energy Levels
Bohr Experiment that was used/What was proposed
Excited electrons and noticed how much energy was released
Chadwick What did they discover?
Discovered Neutron
Chadwick Experiment that was used/What was proposed
Fired Particles at Beryllium and noticed the reflection
Chadwick Additional information
neutrons in the center with protons
Mendeleev
What did they discover?
Discovered the periodic table
Mendeleev Experiment that was used/What was proposed
first put 7 elements in order to atomic weight, place next 7 in order in first next row…. down columns had patterns of similar characteristics later changed the order by atomic number for more consistent patterns
Mendeleev
Predictions of new elements were correct from his periodic table
Proton charge, job, and where it’s found
charge- +1 (positive)
job- Determines element,
Mass, and charge
where- Nucleus
Neutron charge, job, and where it’s found
charge- 0 (neutral)
job- Determines the mass and stability
where it’s found- nucleus
Electron charge, job, and where it’s found
charge- -1 (negative)
job- Determines reactivity and properties
where it’s found- electron cloud
How many electrons are in each level
first level- 2
second level- 8
third level- 18
The central core of an atom is called the hub (true or false)
False - called nucleus
The mass of an electron is about equal to the mass of a proton (true or false)
False - protons and neutrons have same mass
The boss of the atom is the proton (true or false)
True
The atomic number of an element is determined by the number of protons in the nucleus (true or false)
True
The charge is dependent on the # of protons vs # of neutrons (true or false)
False - # of protons vs # electrons
Explain how you would find out the number of neutrons of an atom?
Mass number (Protons and neutrons) - atomic number (# of protons)
What is an ion
charged atom. You make an ion by adding or subtracting electrons from an atom. change only the # of electrons not protons
How do you make a positive and negative ion
if you add more electrons you will make a negative ion and if you take away electrons you will create a positive ion. Ion is dependent on the ratio of electrons and protons.
A positive ion has
more protons than electrons - lose electrons make atom more positive
A negative ion has
more electrons than protons - gain electrons makes atom more negative
What is an isotope?
isotope are two atoms of the same element that have the same number of protons but different number of neutrons and have different masses due to the different number of neutrons.
What is the importance of isotopes
They are important because they can help determine the average atomic mass or atomic weight of an element that is found on the periodic table. The average atomic mass or atomic weight is based off the abundance of the isotopes found in nature of an element. The most common isotope will determine the main part of the atomic weight.
example of an isotope
example of an isotope is Boron - 10 and Boron- 11. both have 5 protons but B-10 has 5 neutrons while Boron -11 has 6 neutrons. The atomic weight is 10.81 meaning there is more Boron - 11 than Boron - 10 since it is closer to 11.
Would you predict that 6 protons and 6 neutrons will make a stable nucleus?
Yes, because the number of protons and neutrons are about equal
stability has to do with # of protons and neutrons. The closer the ratio is one to one the more stable the atom especially smaller atoms. bigger atoms need more neutrons to be more stable.
Transition metals
less reactive metals
good conductors of heat and electricity
used for jewelry and building materials, pigments
Halogen Family
Most reactive nonmetals 7 valence electrons never found unbonded in nature has all 3 states of matter non metals - can be smelly and poisonous
Alkaline earth metals
fairly Reactive metals
2 valence electrons
never found unbonded in nature
important minerals in our bodies
Alkali metals
Most reactive metals 1 valence electrons never found unbonded in nature combine with halogens to make salts soft enough to cut with a butter knife
Noble gases
Non Reactive/inert gases
8 valence electrons
dont react with other elements
found in neon signs, balloons
Transition Metals
Transitions metal are in groups 3 - 12 on the periodic table and change from metallic to dull as you go from left to right across the periodic table.
What do the columns and rows tell you about the elements?
columns tell you how many valence electrons (outer shell electrons) and similar properties in common. Rows tell you how many shells each element will have
What are the properties of all metals?
1 to 3 valence electrons
givers of electrons/lose electrons
make positive ions (cation)
characteristics- good conductor, ductile, malleable, shiny, solid at room temp.
What are the properties of all nonmetal?
5 to 8 valence electrons
takers of electrons/gain electrons
make negative ions (anions)
characteristics- poor conductor, not ductile, not malleable, dull, liquid, solid, or gas at room temp
The atomic radius of elements decreases as you go down the groups on the periodic table (true or false)
False - atomic radius gets bigger down the groups and smaller left to right
The electronegativity is the measure of attraction between the atom’s nucleus and electrons (true or false)
True - electronegativity measure of the tendency of an atom to attract a bonding pair of electrons
Fluorine has a lot of ionization energy (true or false)
True
What is the difference between a Bohr Diagram and Lewis Dot Diagram?
Bohr Diagram show you the set up of all electrons of an atom around the nucleus. Lewis Dot Diagrams is just a picture of the outer electrons or valence electrons that are used to help create chemical bonds between atoms of different elements.
