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Chemistry Unit 2
Terms in this set (41)
A particle smaller than an atom, found within the atom (proton, neutron, electron)
Subatomic particle inside the nucleus, positive charge
Subatomic particle inside nucleus, neutral/ no electric charge
Found in rings of atom, negative electric charge
Positively charged central core of an atom, consisting of protons and neutrons
Each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties; in particular, a radioactive form of an element. (carbon 12 and carbon 14)
the number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table.
Atomic Mass Unit
A unit of mass used to express atomic and molecular weights, equal to one-twelfth of the mass of an atom of carbon-12. It is equal to approximately 1.66 x 10-27 kg.
The total number of protons and neutrons in a nucleus.
Average Atomic Mass
The average atomic mass of an element is the sum of the masses of its isotopes, each multiplied by its natural abundance
Where electrons are when they go around the nucleus of an atom.
Usually refers to electric charge, which is a conserved property of certain subatomic particles that determines their electromagnetic interaction.
Law of Definite Proportions
A given chemical compound always contains its component elements in fixed ratio (by weight) and does not depend on its source and method of preparation.
Law of Multiple Proportions
When two elements combine with each other to form more than one compound, the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.
Law of Definite Compostion
The law of definite composition states that chemical compounds are composed of a fixed ratio of elements as determined by mass. (same as def prop)
Strong Nuclear Force
The force that holds particles together in the atomic nucleus
Photo Electric Effect
Refers to the emission, or ejection, of electrons from the surface of, generally, a metal in response to incident light.
Matter and energy are composed of tiny units of electromagnetic energy called quanta.
5 points of Dalton's Atomic Theory
1. Elements are made of extremely small particles called atoms.
2. Atoms of a given element are identical in size, mass, and other properties; atoms of different elements differ in size, mass, and other properties.
2. Atoms cannot be subdivided, created, or destroyed.
4. Atoms of different elements combine in simple whole-number ratios to form chemical compounds.
5. In chemical reactions, atoms are combined, separated, or rearranged.
Difference between protons, neutrons, electrons in terms of their location in the atom and their charge
Protons- positive, in nucleus
Neutrons- no charge, in nucleus
Electrons- rings around nucleus, negative charge
Isotope vs Ion
An ion is an atom with a net electric charge due to the loss or gain of one or more electrons. An isotope is each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties.
Writing an element in symbol and hyphen notation
Hyphen Notation: Element Name- Mass
Symbol Notation: Mass/ protons SYMBOL
Calculate average atomic mass for an element with 2 or more isotopes
Mass (percent %100) + the second= avg (AMU)
Calculate the relative abundance (percent abundance) of an elements isotopes
Calculate the number of protons, neutrons, and electrons in various isoptopes
P+N= atomic mass
P= atomic number
Determine the charge of an ion knowing the number of subatomic particles in a substance
Look at electrons/ protons
Law of Conservation of Mass
Mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations. According to the law of conservation of mass, the mass of the products in a chemical reaction must equal the mass of the reactants.
Evidence that led to Thomson's model of the atom
- Cathode Ray Tube experiments
- Discovery of the electron as the first subatomic particle (smaller than atom)
-Plum Pudding Model
Millikan's Contribution to the atomic model
Oil Drop experiment
-Quantify the charge of an electron, which greatly contributed to our understanding of the structure of the atom
Evidence that led to Rutherford's model of the atom
-Gold Foil Experiment
-Alpha particles went through sometimes but deflected others
-Positively charged nucleus at the center of the atom
Evidence that led to Bohr's model of the atom
Electrons are contained in energy levels (solar system model)
Quantum model of the atom/ electron cloud model
-Schrodinger: current model with protons and neutrons in nucleus, cloud of electrons
Chadwick's contribution to the atomic model
-Discovered neutrons in atoms
Small sphere, indivisible (460 BC)
First to back up idea of atoms as the smallest particles with scientific evidence/ experiments (1805)
Discovery of the electron as the first subatomic particle (smaller than atom)
-Plum pudding model (1897)
Positively charged nucleus at the center of the atom (1911)
Electrons are contained in energy levels (1913)
Schrodinger (electron cloud) Model
Dense nucleus with protons and neutrons surrounded by a cloud of electrons
Calculate the mass, number of moles, number of molecules/formula units, or atoms given an initial amount of one of these
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