Untitled Quiz

An element is a pure substance that cannot be broken down into simpler substances by a chemical reaction.

Each element is identified by a one- or two-letter symbol.

The periodic table is an organized chart that displays all known elements.

<p>The position of an element in the periodic table tells us much about its chemical properties.</p> Signup and view all the answers

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

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

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

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

<p>Metals, nonmetals, and metalloids</p> Signup and view all the answers

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

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

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

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

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

<p>A chemical formula is a symbolic representation of a compound that shows the types and number of atoms present.</p> Signup and view all the answers

<p>The subscripts in a chemical formula represent the ratio of atoms in the compound.</p> Signup and view all the answers

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

<p>Protons: positively charged particles located in the nucleus; Neutrons: neutral particles located in the nucleus; Electrons: negatively charged particles that orbit the nucleus.</p> Signup and view all the answers

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

<p>The nucleus is the dense, positively charged center of an atom that contains protons and neutrons.</p> Signup and view all the answers

<p>The electron cloud is the region of space around the nucleus where electrons are likely to be found.</p> Signup and view all the answers

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

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

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

<p>A neutral atom is an atom that has no net overall charge, meaning the number of protons is equal to the number of electrons.</p> Signup and view all the answers

<p>In a neutral atom, the atomic number is equal to the number of protons, which is also equal to the number of electrons.</p> Signup and view all the answers

<p>Isotopes are atoms of the same element that have the same number of protons but differ in the number of neutrons.</p> Signup and view all the answers

<p>Mass number is the sum of the number of protons and neutrons in an atom's nucleus.</p> Signup and view all the answers

<p>The number of neutrons can be calculated by subtracting the atomic number (number of protons) from the mass number.</p> Signup and view all the answers

<p>Atomic weight is the weighted average of the masses of all naturally occurring isotopes of an element, expressed in atomic mass units.</p> Signup and view all the answers

<p>The atomic weight of an element can be determined by multiplying the isotopic abundance (fractional abundance) of each isotope by its mass and then adding the products together.</p> Signup and view all the answers

<p>A period in the periodic table is a horizontal row of elements.</p> Signup and view all the answers

<p>Group 1A</p> Signup and view all the answers

<p>Group 2A</p> Signup and view all the answers

<p>Alkali metals are soft, silvery-white metals with low melting points and high reactivity. They are good conductors of heat and electricity.</p> Signup and view all the answers

<p>Alkaline earth metals are silvery-white, denser, and harder than alkali metals. They are also less reactive than alkali metals but still react with water to form basic solutions.</p> Signup and view all the answers

<p>Group 7A</p> Signup and view all the answers

<p>Group 8A</p> Signup and view all the answers

<p>Halogens are nonmetals with a variety of colors and states at room temperature. They are highly reactive and tend to form negative ions.</p> Signup and view all the answers

<p>Noble gases are colorless, odorless, tasteless, and unreactive gases that are stable due to their full outer electron shells. They are found in trace amounts in the atmosphere.</p> Signup and view all the answers

<p>Classical atomic theory predicted that electrons orbiting the nucleus would lose energy and spiral into the nucleus due to acceleration, leading to the collapse of the atom. However, atoms exist and are stable, so classical predictions were contradicted by experiment, suggesting the need for a new theory.</p> Signup and view all the answers

<p>The line spectrum observed for atoms provides evidence that electrons are not continuous but exist in specific energy levels or orbits, resulting in distinct emissions of light at specific wavelengths.</p> Signup and view all the answers

<p>Max Planck proposed that energy is not continuous but exists in discrete packets or quanta, meaning energy can only be absorbed or emitted in multiples of a fundamental unit called a quantum.</p> Signup and view all the answers

<p>Einstein proposed that light exists as quantized packets of energy called photons, which have both wave-like and particle-like properties.</p> Signup and view all the answers

<ol> <li>Electrons can only exist in specific allowed orbits around the nucleus. 2. Within a specific orbit, an electron does not radiate energy. 3. An electron emits or absorbs energy when it transitions between orbits.</li> </ol> Signup and view all the answers

<p>The quantum theory of the atom proposes that electrons exist in discrete energy levels or states. When an electron transitions from a higher energy level to a lower level, it releases a photon of light with specific energy equal to the difference between the two levels. This explains the observed line spectra of hydrogen as each line corresponds to a specific energy transition.</p> Signup and view all the answers

<p>Bohr's theory was only able to explain the spectra of hydrogen because it assumed a simple, one-electron system. Atoms with more than one electron have more complex interactions and energy levels, making Bohr's theory insufficient.</p> Signup and view all the answers

<p>Wave-particle duality is the concept that light and matter exhibit both wave-like and particle-like properties.</p> Signup and view all the answers

<p>de Broglie proposed that if light can exhibit wave-particle duality, then particles such as electrons should also have wave-like properties.</p> Signup and view all the answers

<p>The quantum mechanics model describes electrons as spread-out matter waves that are confined to specific regions of space called orbitals. The location of an electron within an orbital is uncertain, but it is possible to determine the probability of finding the electron at a particular location.</p> Signup and view all the answers

<p>Quantum numbers are a set of values that specify the unique properties of an electron in an atom. These numbers describe an electron's energy level, shape of orbital, spatial orientation in space, and spin.</p> Signup and view all the answers

<p>The principal quantum number (n) defines the electron's energy level, with higher values indicating higher energy levels. It also approximately indicates the average distance of an electron from the nucleus.</p> Signup and view all the answers

<p>The angular momentum quantum number (l) describes the shape of an electron's orbital and its spatial distribution around the nucleus. Each value of l corresponds to a specific orbital shape: l=0 for s orbitals (spherical), l= 1 for p orbitals (dumbbell shape), l=2 for d orbitals, and so on.</p> Signup and view all the answers

<p>The magnetic quantum number (ml) describes the spatial orientation of an electron's orbital in space. It can take values from -l to +l, including 0, and governs the direction of the orbital's shape relative to a set of axes.</p> Signup and view all the answers

<p>The spin quantum number (ms) describes the intrinsic angular momentum of an electron, which is analogous to the spin of a charged object. It can take values of either +1/2 or -1/2, representing the two possible spin states of an electron.</p> Signup and view all the answers

<p>An electron configuration shows the distribution of electrons among the different energy levels (shells and subshells) in an atom.</p> Signup and view all the answers

<p>The ground state electron configuration represents the lowest energy arrangement of electrons in an atom.</p> Signup and view all the answers

<ol> <li>Electrons fill orbitals starting with the lowest energy level, usually the 1s orbital. 2. Orbitals are filled in increasing order of energy. 3. Each orbital can hold a maximum of two electrons, with opposite spins. 4. When orbitals within a subshell are equal in energy, one electron is added to each orbital until all are half-filled, then the orbitals are filled completely.</li> </ol> Signup and view all the answers

<p>Noble gas notation is a shorthand for writing electron configurations, where you use the symbol of the preceding noble gas followed by the electronic configuration of the remaining electrons for the element.</p> Signup and view all the answers

<p>The valence shell is the outermost electron shell of an atom, containing the highest principal quantum number (n).</p> Signup and view all the answers

<p>Valence electrons are the electrons that reside in the outermost electron shell of an atom, typically involved in chemical reactions and bonding.</p> Signup and view all the answers

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

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

<p>Except for helium, the group number on the periodic table (1A to 8A) corresponds to the number of valence electrons for the main group elements.</p> Signup and view all the answers

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

<p>Helium has only two valence electrons, even though it is in Group 8A (noble gases), which typically have eight valence electrons. This exception arises from the fact that helium's first electron shell is filled with only two electrons, while other noble gases have filled second or higher shells.</p> Signup and view all the answers