Flashcards
Chemistry - Unit 2
Cards in this deck (29)
- 1Dalton's atomic Theory1. Elements are composed of tiny, indivisible particles called atoms
2. Atoms of the same element are identical, and the atoms of any element are different from the atoms of any other element.
3. Atoms of different elements can chemically combine with one another in simple whole-number ratios to form compounds.
4. Chemical reactions occur when atoms separate and rearrange. Atoms of one element can never be changed into atoms of another element as a result of a chemical reaction. - 2Elementsubstance that cannot be changed into simpler substances under normal laboratory conditions
- 3Atomthe smallest particle of an element that retains the properties of the element
- 4Development of the Atomic Theory: Model 1
- 5Development of the Atomic Theory: Model 2Thompson’s cathode ray tube experiment (1897): existence of a subatomic negative particle (electron) --> led to Plum Pudding Model
- 6Development of the Atomic Theory: Model 3Rutherford’s gold foil experiment (1911): existence of a small, dense, positively charged nucleus surrounded by mostly empty space --> Led to nuclear atom planetary model
- 73 Subatomic particles in the nucleus: Comparisons
- 8Atomic Numbernumber of protons in the nucleus.
all atoms of a given element have the same number of protons in the nucleus; each element has a different number of protons; the periodic table is organized in order of increasing atomic number - 9Mass Numbersum of protons and neutrons in the nucleus
- 10Isotope Conventions1) superscripted to the left: mass number
subscripted to left: atomic number
charge: to the right of symbol (i.e. 1 +)
2) Element name - mass number - 11Neutral atom vs. IonNeutral: p+ equals e-
Ion: p+ does not equal e- - 12Cationpositive charge
- 13AnionNegative charge
- 14isotope:atoms of the same element (same atomic number) that have different numbers of neutrons (different mass numbers)
(I.e. carbon-12, carbon-13)
Isotopes are chemically alike because they have the same number of protons and electrons which are responsible for chemical behavior - 15Allotropessamples of the same element that have different properties because of differences in the 3-dimensional structure in which the atoms are bonded
- 16Average Atomic Massa weighted average of the isotopes of the element.
weighted average = (% A)(value of A) + (% B)(value of B) + … - 17Ion:An atom gains or loses electrons to become an ion
- 18Periodic Table- Columns (vertical) are called groups
- Rows (horizontal) are called periods - 19Periodic LawWhen the elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties
- 20Electronssubatomic particles with a negative charge
- 21ProtonsSubatomic particles with positive charge
- 22NeutronsSubatomic particles with no charge (neutral)
- 23Angstrom- Used to measure the radii of atoms
- 1 angstrom = 1 x 10^-10 m
- To convert to angstroms set up a proportion
1A/ 1x10^-10 m = xA/(number to convert) - 24Scanning Tunneling Microscopy- a microscope that can view atoms
- a teqnique used to visualize atoms - 25How They determined Natural Abundance- used mass spectroscopy
- Atoms that have turned into ions are placed in a magnetic field
- Charged particles are attracted upward - depending on their mass their path gets distorted a certain degree
the light particles are very bent
- This helps determine which the percentage of each isotope. - 26How to find the Charge of a given atomprotons - electrons = charge
- 27Comparison of Protons and Electrons in the NucleusNumber of electrons must equal the number of protons (atoms are electrically neutral)
- 28amuatomic mass unit
made up unit used to talk about the mass of a particle - 29Nucleuscentral core of an atom and is composed of protons and neutrons
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- Flashcards on Chemistry - Unit 2 , created by mclanem on 02/11/2014.
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