Midterm 1 Flashcards
(177 cards)
What can matter be separated into
Pure substances and mixtures
What can pure substances be separated into
Elements and compounds
What can mixtures be separated into
Homogeneous and heterogeneous
What is the difference between elements and compounds
Elements are made of one type of atom and compounds are made of more than one type of atom
What are the five hypothesis’ of dalton’s atomic theory
1) matter is composed of extremely small particles called atoms
2) an element consists of only one type of atom
3) atoms of one element differ in properties from atoms of all other elements
4) a compound consists of atoms of two or more elements combined in a small, whole number ratio
5) atoms are neither created nor destroyed during a chemical change
What three laws did dalton’s atomic model account for
1)Law or conservation of matter
2) law of constant composition
3) law of multiple proportions (two elements can react to form more than one compound), carbon oxygen can form one thing or another thing
What did JJ Thompson show and through what experiment
The existence of electrons through the cathode ray tube
What were JJ Thompson’s 3 conclusions on electrons
1) negatively charged particles
2) less massive than atoms
3) particles were indistinguishable regardless of the source material (cathode ray)
What were the two things Millikan calculated in the oil drop experiment
1) charge of an electron
2) used Thomson’s charge to mass ratio to calculate the mass of an electron
What does Thomson’s plum pudding (raisin bun) model show
Electrons are dispersed in a cloud of positively charged matter
What is the modern representation of the atomic structure called
And what did it show
The nuclear atom
Showed that a positively charged mass is present in the atom and there was a lot of space
Atomic symbols: What does the left superscript show
Mass number
What is mass number
Number of protons + neutrons
Atomic symbols: what does a left subscript show
Atomic number
What is atomic number
=protons = electrons in a neutral atom
How to determine the number of neutrons in an atom
Mass #- atomic #
(Left superscript-left subscript)
What are isotopes
Atoms of the SAME element with the SAME # of protons but DIFF # of neutrons
What is atomic mass and where is it on the periodic table
An average # based on the amount of each isotope in nature
Located in the bottom of each element
Where is atomic number on the periodic table
Top left
What are ions
An atom or group of atoms that carry a net positive or negative charge
What is a cation and what is it’s charge
Formed when an atom LOSES electrons (+ charge)
What is an anion and what is it’s charged
Firmed when an atom GAINS electrons (- charged)
Why do ions form and when
Some atoms have a tendency to lose electrons and others have the tendency to gain electrons
Happens during chemical reactions
What is a column of elements called
And what do they have in common
Group
Have similar properties and reactivities