Atoms, Molecules, and Ions - Gen Chem 1

It states that the percent composition of a compound must have a unique value regardless of the sample analyzed.

The Law of Multiple Proportions states that if two elements form multiple compounds, the mass ratios of one element with a fixed mass of the other are in small whole numbers.

Rutherford concluded that the atom consists of a small, dense, positive nucleus surrounded by electrons at large distances.

<p>He expected the alpha particles to pass through the gold foil without significant deflection.</p> Signup and view all the answers

<p>Some alpha particles were deflected at large angles, indicating the presence of a dense, positively charged center.</p> Signup and view all the answers

<p>The atomic number is equal to the number of protons in the nucleus and determines the identity of an element.</p> Signup and view all the answers

<p>It indicated that atoms are indestructible, and the same atoms must exist post-reaction as before.</p> Signup and view all the answers

<p>Thomson's model depicted electrons as being embedded within a positively charged 'pudding'.</p> Signup and view all the answers

<p>Dalton's Atomic Theory proposes that all matter is made of tiny indivisible particles called atoms, which combine in fixed ratios to form compounds.</p> Signup and view all the answers

<p>The Law of Conservation of Mass states that in a chemical reaction, the total mass of reactants is equal to the total mass of products, meaning mass is neither created nor destroyed.</p> Signup and view all the answers

<p>The atomic number is the number of protons in an atom's nucleus, while the mass number is the total number of protons and neutrons combined.</p> Signup and view all the answers

<p>Isotopes are atoms of the same element that have different numbers of neutrons, resulting in different mass numbers; they are represented with isotopic symbols such as $^{A}_{Z}X$, where A is the mass number and Z is the atomic number.</p> Signup and view all the answers

<p>An atom is a single unit of an element, such as sodium (Na), while a molecule is formed when two or more atoms bond together, such as water (H₂O).</p> Signup and view all the answers

<p>The Law of Definite Proportions states that a chemical compound always contains the same proportion of elements by mass, regardless of the amount or source of the compound.</p> Signup and view all the answers

<p>The isotopic symbol for Carbon-14 is written as $^{14}_{6}C$.</p> Signup and view all the answers

<p>Ions are charged particles that result from the loss or gain of electrons, and they play a crucial role in forming ionic compounds by attracting opposite charges.</p> Signup and view all the answers

<p>The law of conservation of mass states that the mass of reactants equals the mass of products. In the reaction, 10.0g of CaCO3 yields 4.4g of CO2 and 5.6g of CaO, confirming the total mass remains 10.0g.</p> Signup and view all the answers

<p>The law of definite proportions states that a compound contains the same elements in fixed proportions by mass. For water, it is always composed of 11.19% hydrogen and 88.81% oxygen, irrespective of the sample's source.</p> Signup and view all the answers

<p>The law of multiple proportions indicates that when two elements form different compounds, the masses of one element that combine with a fixed mass of the other are in a ratio of small whole numbers.</p> Signup and view all the answers

<p>Dalton's atomic theory states that elements consist of atoms, which are indivisible; all atoms of an element are identical; compounds are formed by combining atoms in whole number ratios; and atoms are rearranged in chemical reactions without being created or destroyed.</p> Signup and view all the answers

<p>The atomic mass of an element is the weighted average of the masses of its isotopes, reflecting the percentage abundance of each isotope, which results in a non-integer value.</p> Signup and view all the answers

<p>Dalton's first postulate, stating that atoms cannot be created or destroyed, was proven incorrect through the discovery of nuclear fission, where atoms can be split.</p> Signup and view all the answers

<p>Dalton's second postulate is contradicted by the existence of isotopes, which are variants of the same element with different masses.</p> Signup and view all the answers

<p>To calculate the weighted average, multiply the mass of each isotope by its percent abundance, sum these products, and then divide by 100.</p> Signup and view all the answers

<p>A molecular formula provides the actual number of atoms of each element in a molecule, while an empirical formula shows the simplest ratio of the atoms.</p> Signup and view all the answers

<p>According to the reaction, 224.4g of KOH reacts with 88.0g of CO2 to produce 176.4g of potassium carbonate, after accounting for 36.0g of water produced.</p> Signup and view all the answers

<p>The structural formula displays not only the types and numbers of atoms but also how they are connected to each other.</p> Signup and view all the answers

<p>The reaction demonstrates conservation of mass as the total mass of the reactants (KOH and CO2) equals the total mass of the products (K2CO3 and H2O), ensuring no mass is lost.</p> Signup and view all the answers

<p>Isotopes are variants of a chemical element that have the same number of protons but differ in the number of neutrons, leading to different atomic masses.</p> Signup and view all the answers

<p>Carbon-12 is the most abundant isotope, making up almost 99% of naturally occurring carbon due to its stability and the processes by which elements are formed.</p> Signup and view all the answers

<p>An example of a molecule is oxygen gas, represented by the molecular formula O2, indicating that two oxygen atoms are chemically bonded together.</p> Signup and view all the answers

<p>Chemical bonding determines the geometry, reactivity, and physical properties of molecules, influencing how they interact with other substances.</p> Signup and view all the answers

<p>A cation is a positively charged ion formed by losing electrons, while an anion is a negatively charged ion formed by gaining electrons.</p> Signup and view all the answers

<p>The total charge of an ionic compound is neutral when the sum of positive and negative charges equals zero.</p> Signup and view all the answers

<p>The empirical formula of hydrogen peroxide is HO, which shows the simplest ratio of atoms, while its molecular formula H2O2 indicates the actual number of each atom in the molecule.</p> Signup and view all the answers

<p>Dalton's model, proposed in 1803, was significant because it introduced the idea of atoms as indivisible particles that compose matter, forming the foundation of modern atomic theory.</p> Signup and view all the answers

<p>The sulfate ion has a charge of -2, indicating that it has gained two electrons during its formation.</p> Signup and view all the answers

<p>Simple ions consist of only one atom, while polyatomic ions are composed of two or more atoms bonded together, carrying a net charge.</p> Signup and view all the answers

<p>Thomson's 'plum-pudding' model proposed that electrons are embedded in a positively charged 'soup,' suggesting the atom is divisible and leading to further studies of its structure.</p> Signup and view all the answers

<p>The charge-cloud model describes electron behavior as a probability cloud surrounding the nucleus, emphasizing that electrons do not have fixed orbits.</p> Signup and view all the answers