Chemistry Test Chapter 3 Flashcards

The smallest particle in an element that retains its identity in a chemical reaction.

Democritus. He believed that atoms were indivisible and indestructible.

Indivisible.

<p>They didn't explain chemical behavior and they lacked experimental support.</p> Signup and view all the answers

<p>1.) All chemists accepted that elements cannot be further broken down by ordinary chemical means. 2.) Elements combine to form compounds that have different physical and chemical properties than the elements that formed them.</p> Signup and view all the answers

<p>The controversy was whether elements always combine in the same ratio when forming a particular compound.</p> Signup and view all the answers

<p>Mass is neither created nor destroyed during ordinary chemical reactions or physical changes.</p> Signup and view all the answers

<p>A chemical compound contains the same elements in exactly the same proportions by mass regardless of the size of the sample of the compound.</p> Signup and view all the answers

<p>If 2 or more different compounds are composed of the same 2 elements, then the ratio of the masses of the 2nd element combined with a certain mass of the 1st element is always a ratio of small whole numbers.</p> Signup and view all the answers

<p>John Dalton used the scientific method to turn Democritus's ideas on atoms into scientific theory. He said that elements were composed of atoms and that only whole numbers of atoms can combine to form compounds.</p> Signup and view all the answers

<p>1.) All elements are composed of atoms. 2.) Atoms of the same element are identical. 3.) Atoms cannot be subdivided, created, nor destroyed. 4.) Atoms of different elements can physically mix together or chemically combine in simple whole number ratios to form compounds. 5.) Chemical reactions occur when atoms are separated, joined or rearranged.</p> Signup and view all the answers

<p>False</p> Signup and view all the answers

<p>Unable to be cut.</p> Signup and view all the answers

<p>A very small region located at the center of the atom.</p> Signup and view all the answers

<p>Negatively charged particles that orbit the nucleus.</p> Signup and view all the answers

<p>A positively charged particle found inside the nucleus with the same mass as the neutron.</p> Signup and view all the answers

<p>A neutrally charged particle found in the nucleus, with the same mass as a proton.</p> Signup and view all the answers

<p>A device used to pass electric currents through gases at lower pressure.</p> Signup and view all the answers

<p>Cathode - negative end, Anode - positive end.</p> Signup and view all the answers

<p>Cathode rays are deflected away from electrically charged plates and magnets.</p> Signup and view all the answers

<p>True</p> Signup and view all the answers

<p>J.J. Thomson discovered the electron using the cathode ray. He concluded that a cathode-ray is composed of identical negatively charged particles called electrons.</p> Signup and view all the answers

<p>Eugen Goldstein discovered the proton by observing a cathode ray tube and finding rays travelling in the direction opposite to that of the cathode ray.</p> Signup and view all the answers

<p>James Chadwick.</p> Signup and view all the answers

<p>He discovered that the quantity of charge carried by an electron is 1 unit of negative charge, and he discovered the mass of a proton.</p> Signup and view all the answers

<p>Plum-pudding model. It describes electrons stuck into a lump of positive charge.</p> Signup and view all the answers

<p>All positive charge and mass are located in a small region called the nucleus, and the atom is mostly empty space.</p> Signup and view all the answers

<p>In the nucleus.</p> Signup and view all the answers

<p>The tiny central core of atoms that contains both protons and neutrons and has a positive charge.</p> Signup and view all the answers

<p>Because they contain equal numbers of protons and electrons.</p> Signup and view all the answers

<p>He was Rutherford's student, who proposed a model in which the negative electrons surrounded the positive nucleus.</p> Signup and view all the answers

<p>When two protons are extremely close to each other, there is a strong attraction between them, including interactions between protons and neutrons.</p> Signup and view all the answers

<p>The radius of an atom is the distance from the center of the nucleus to the outer portion of its electron cloud. The unit is the picometer.</p> Signup and view all the answers

<p>Scanning tunneling microscope.</p> Signup and view all the answers

<p>Elements are different because they contain different numbers of protons and the atomic number of an element is the number of protons in the nucleus of an atom of that element.</p> Signup and view all the answers

<p>Atomic number is not a decimal, atomic mass is.</p> Signup and view all the answers

<p>Atoms that have the same number of protons but different numbers of neutrons. They're the same elements.</p> Signup and view all the answers

<p>Atoms that have the same number of protons but different numbers of neutrons. They are the same element but have different atomic masses.</p> Signup and view all the answers

<p>Mass number and atomic mass.</p> Signup and view all the answers

<p>The superscript indicates the mass number and the subscript indicates the atomic number.</p> Signup and view all the answers

<p>The mass number is written with a hyphen after the name of the element.</p> Signup and view all the answers

<p>They have identical numbers of protons and electrons.</p> Signup and view all the answers

<p>A general term for a specific isotope of an element.</p> Signup and view all the answers

<p>Atoms that have either gained or lost electrons.</p> Signup and view all the answers

<p>Negative ion (gains electrons) called anions, and positive ion (loses electrons) called cations.</p> Signup and view all the answers

<p>Tells you the number of molecules (compounds) there are.</p> Signup and view all the answers

<p>This tells you the number of atoms there are.</p> Signup and view all the answers

<p>A mixture of 2 or more isotopes.</p> Signup and view all the answers

<p>Mass and natural percent abundance.</p> Signup and view all the answers

<p>Neutrons plus protons equal the mass number.</p> Signup and view all the answers

<p>Atomic mass unit.</p> Signup and view all the answers

<p>Unit of mass equal to 1/12th of the mass of a carbon-12 atom, used to compare relative masses.</p> Signup and view all the answers

<p>Multiply the mass of each isotope by its natural abundance, then add the product.</p> Signup and view all the answers

<p>The SI unit for amount of substance.</p> Signup and view all the answers

<p>The number of particles in exactly one mole of a pure substance.</p> Signup and view all the answers

<p>Molar mass is the mass of one mole of a pure substance.</p> Signup and view all the answers

<p>Quantitative analysis of chemical reactions.</p> Signup and view all the answers