Chemistry Chapter 3 Flashcards

A chemical compound contains the same elements in exactly the same proportions by mass regardless of the size of the sample or source of the compound.

If two or more different compounds are composed of the same two elements, then the ratio of the masses of the second element combined with a certain mass of the first element is always a ratio of small whole numbers.

<p>The smallest unit of an element that maintains the properties of that element.</p> Signup and view all the answers

<p>nuclear forces</p> Signup and view all the answers

<p>Exactly 1/12 the mass of a carbon-12 atom.</p> Signup and view all the answers

<p>The number of protons in the nucleus.</p> Signup and view all the answers

<p>The weighted average of the atomic masses of the naturally occurring isotopes of an element.</p> Signup and view all the answers

<p>6.022 x 10²³</p> Signup and view all the answers

<p>Atoms of the same element that have different masses.</p> Signup and view all the answers

<p>The total number of protons and neutrons in the nucleus.</p> Signup and view all the answers

<p>The mass of one mole of the substance, written in g/mol.</p> Signup and view all the answers

<p>The SI unit for a substance; it is the amount of a substance that contains as many particles as there are atoms in exactly 12g of carbon-12.</p> Signup and view all the answers

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

<p>Thompson = Discovered electrons and found that the electron has a very large charge for its tiny mass. Millikan = Found the exact mass of the electron and confirmed its negative charge. Rutherford = Discovered that the nucleus is a very small positively charged region inside an atom. Democritus = Thought the atom was the basic particle and indivisible.</p> Signup and view all the answers

<p>A thin piece of gold foil was bombarded with alpha particles, and it was found that about 1 in 8000 were redirected back towards the source.</p> Signup and view all the answers

<p>The metal disk connected to the negative terminal of the voltage source.</p> Signup and view all the answers

<p>The metal disk connected to the positive terminal of the voltage source.</p> Signup and view all the answers

<p>When a current was passed through a cathode-ray tube, the surface of the tube directly opposite the cathode glowed.</p> Signup and view all the answers

<p>He did not believe in atoms and thought all matter was continuous.</p> Signup and view all the answers

<p>The transformation of a substance or substances into one or more new substances.</p> Signup and view all the answers

<p>A very small region located near the center of the atom that contains at least one proton and usually at least one neutron.</p> Signup and view all the answers

<p>A neutrally charged atom.</p> Signup and view all the answers

<p>A positively charged atom.</p> Signup and view all the answers

<p>A negatively charged atom.</p> Signup and view all the answers

<p>Neutrons, electrons, and protons.</p> Signup and view all the answers

<p>Positively charged particles with 4 times the mass of hydrogen.</p> Signup and view all the answers

<p>They thought the mass was distributed evenly throughout the atom.</p> Signup and view all the answers

<p>The mass number separated with a dash after the name of the element (e.g., uranium-235).</p> Signup and view all the answers

<p>The superscript indicates the mass number, and the subscript indicates the atomic number (e.g., 235/92).</p> Signup and view all the answers

<p>number of neutrons</p> Signup and view all the answers