Chemistry

Half Life

The time required for the amount of reactant to drop to one half its initial value.

Mass Number

The total number of protons and neutrons in an atom or ion.

Lead

This element has the highest atomic number of all the stable elements ​and its only common allotrope is face centered cubic. name this heaviest nonradioactive element, a post transition metal, that was formerly used in pipes and paints, but due to its poisonous properties, is now limited to use in batteries, bullets and as radiation shields with chemical symbol Pb.

Carbon

This element is necessary for organic chemistry

Gas (gaseous, gases, vapor)

Triple point of a substance is the temperature and pressure at which that substance can simultaneously exist as a solid, liquid and what other state of matter?

Double Replacement Reaction (aka Double Displacement)

Type of chemical reaction where two compounds react, and the positive ions (cation) and the negative ions (anion) of the two reactants switch places, forming two new compounds or products.

proteins

considered to be polymers of amino acids

Boron

element represented by the symbol B

Strontium

element represented by the symbol Sr

Halogens Group 7A.

fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). 7 valence electrons in their highest-energy orbitals

Compound

A material formed from elements chemically combined in definite proportions by mass.

Anion

A negatively charged ion.

Alpha Particle

A particle that is commonly ejected from radioactive nuclei, consisting of two protons and two neutrons. All of these particle are helium nuclei

Cation

A positively charged ion

Catalyst

A substance that increases the rate of a chemical reaction, without being consumed or produced by the reaction.

Decomposition Reaction

A type of chemical reaction in which a single compound breaks down into two or more elements or new compounds. These reactions often involve an energy source such as heat, light, or electricity that breaks apart the bonds of compounds.

Synthesis Reaction

A type of reaction in which multiple reactants combine to form a single product. They release energy in the form of heat and light, so they are exothermic

nitrogen

After carbon, hydrogen, and oxygen, the next most abundant element in proteins is

Silver

Atomic Symbol Ag

Gold

Atomic Symbol Au

Iron

Atomic Symbol Fe

Mercury

Atomic Symbol Hg

Potassium

Atomic Symbol K

Sodium

Atomic Symbol Na

Lead

Atomic Symbol Pb

Tin

Atomic Symbol Sn

Tungsten

Atomic Symbol W

Isotope

Atoms or ions of an element with different numbers of neutrons in their atomic nucleus.

Marie Curie

Awarded the Nobel Prize in 1911 for the discovery of the radioactive elements, radium and polonium

Aluminum

Because ______________ exists only in a +3 oxidation state, it takes three moles of electrons to produce one mole of _________________; as a result, it has been estimated that 5% of all electricity in the U.S. goes to purifying _____________. Atomic Symbol Al, Atomic Number 13

Nitrogen

Because _______________ gas is extremely stable, N2 is unusable for many biological and chemical purposes. To make it useful, it often undergoes fixation to convert it into usable ______________________ species such as the ammonium ion (NH4+)—as it is by bacteria in the root nodules of legume plants—or ammonia gas (NH3), as is done industrially in the Haber-Bosch process. Atomic Symbol N, Atomic Number 7

Oxygen

Because ________________ is easily capable of accepting electrons, reactions in which a species gives up electrons are known as oxidation reactions. Atomic Symbol O, Atomic Number 8

Helium

Because of their different quantum properties (the __________-3 nucleus is a fermion, while the __________-4 nucleus is a boson), the isotopes of __________ actually have significantly different physical properties. __________-4 can exist in a zero-viscosity state known as superfluidity when its temperature drops below the lambda point. Atomic Symbol He, Atomic Number 2

Acid

A chemical species that donates protons or hydrogen ions and/or accepts electrons.

sulfur

All proteins contain at least 5 specific elements. Four of them are carbon, oxygen, hydrogen, and nitrogen. What is the fifth element?

Mercury

Alloys of __________________ with other metals are called amalgams, some of which have been used as dental fillings. Chronic exposure to mercury can cause psychological problems; its use in hatmaking led to the expression "mad as a hatter." More recently, concerns about exposure have led to the banning of it in thermometers. Atomic Symbol Hg, Atomic Number 80

electrons

Ammonia can be considered a Lewis base because it can donate

Gold

Among all metals, it has the highest electronegativity and electron affinity; it occasionally is found in a -1 oxidation state as Au-. Widely used in jewelry, it also has a number of scientific uses. Atomic Symbol Au, Atomic Number 79

Ion

An atom or molecule that has acquired a charge by either gaining or losing electrons.

Beta Particle

An electron emitted by an unstable nucleus, when a neutron decays into a proton and an electron.

Alkaline Earth Metals

Any of the divalent strongly basic metals of group II of the periodic table comprising beryllium, magnesium, calcium, strontium, barium, and radium

Alkali Metals

Any of the elements lithium, sodium, potassium, rubidium, cesium, and francium, occupying Group 1A of the periodic table. They are very reactive, electropositive, monovalent metals forming strongly alkaline hydroxides.

Gold

Ernest Rutherford's ______ foil experiment demonstrated the existence of a positively charged nucleus. Scanning electron microscopy (SEM) often requires that specimens be "sputtered," or thinly coated, with ______ atoms to allow imaging. Suspensions of ______ compounds have been used to treat rheumatoid arthritis. Atomic Symbol Au, Atomic Number 79

First Law of Thermodynamics

Conservation of Energy. Energy can be neither created nor destroyed; the energy of the universe is constant.

Nitrogen

Conversely, its stability makes it useful in preventing unwanted combustion reactions. It also has a relatively low boiling point (-196°C), which makes liquid ________________ useful as a refrigerant. Atomic Symbol N, Atomic Number 7

Oxygen

Diatomic ________________ is, despite having an even number of electrons, paramagnetic, meaning it has unpaired electrons. This points out a problem with traditional valence bond theories, which predict that ___________ should be diamagnetic; molecular orbital theory correctly explains this behavior. Atomic Symbol O, Atomic Number 8

Allotrope

Different forms of the same element. Ex: Graphite, diamond, coal are all forms of carbon

Rubidium

Element represented by the symbol Rb

Second Law of Thermodynamics

Entropy increases over time. Another way of stating this law is to say that heat cannot flow, on its own, from an area of cold to an area of hot.

Avogadro's Law

Equal volumes of gases under identical temperature and pressure conditions will contain equal numbers of particles (atoms, ion, molecules, electrons, etc.).

Carbon

Fullerenes such as buckyballs and _______ nanotubes, on the other hand, are generally produced synthetically; buckyballs are roughly spherical. More recently, graphene, which is a single layer of atoms shaped like graphite, has proven to have remarkable properties; for example, it is nearly transparent while being about 200 times stronger than an equivalent mass of steel. Atomic Symbol C, Atomic Number 6

Chlorofluorocarbons

Greenhouse gases are called CFC. What does CFC stand for?

Noble Gases

Group 8A. Name comes from the fact that these elements are virtually unreactive towards other elements or compounds.

Albert Einstein

He explained the photoelectric effect

Antoine Lavoisier

He first stated the law of conservation of mass. Killed during the French Revolution

Dmitri Mendeleev

Name the person who developed a table of elements which revealed regularities in elemental properties in 1869

HELIUM, NEON, ARGON, KRYPTON, XENON, RADON

Name the six noble gases

Two

How many electrons can occupy an s orbital?

period

In the periodic table, which of the following identifies a horizontal row?

Group 4A

Includes the nonmetal carbon (C), the metalloids silicon (Si) and germanium (Ge), the metals tin (Sn) and lead (Pb), and the yet-unnamed artificially-produced element ununquadium (Uuq).

Sulfur

Industrially, though, the majority of ______________ is used to make sulfuric acid, H2SO4 (in fact, sulfuric acid is the most widely produced chemical in the chemical industry). ___________ compounds are noted for their strong and unpleasant odors; small quantities of hydrogen sulfide, H2S, are frequently added to natural gas, which is normally odorless, to help detect gas leaks. Atomic Symbol S, Atomic Number 16

Iron

It can react with oxygen in the air to form ____(III) oxide, Fe2O3, in a relatively slow but exothermic process; this process is used in "all-day" heat patches. Hydrated ____(III) oxide is better known as rust; rust only forms when ____ is exposed to both oxygen and water.

Aluminum

It is found in the mineral corundum, which is found in many gems, including sapphires and rubies; the specific impurities found in a gem determine its color. It is also found in aluminosilicates such as feldspar. Atomic Symbol Al, Atomic Number 13

Carbon

It is found, by definition, in all organic compounds. It is the fourth most abundant element in the Universe. It has three major isotopes: isotope 12, which is stable; isotope 13, which is used in NMR spectroscopy; and isotope 14, which is radioactive and is the basis of _______ dating. Atomic Symbol C, Atomic Number 6

Sulfur

It is most often isolated by injecting superheated steam into the ground in the Frasch process. As an element, it is used in the vulcanization process to cross-link the polymer strands of rubber to increase rubber's strength; similarly, ________-_________ bonds hold many proteins together. Atomic Symbol S, Atomic Number 16

Mercury

It is one of just two elements that is a liquid at standard temperature and pressure (the only other one is bromine). It has been known since antiquity, and is found in ores such as cinnabar. Atomic Symbol Hg, Atomic Number 80

Nitrogen

It is the most abundant element in Earth's atmosphere. _____________________________, which was first isolated as "noxious air" by Daniel Rutherford, exists primarily as a diatomic molecule containing two triple-bonded nitrogen atoms (N2). Atomic Symbol N, Atomic Number 7

Iron

It is the most common metal in the Earth, and one of the major components of the core as well. ________was known to the ancients; its atomic symbol Fe comes from the Latin name ferrum. Atomic Symbol Fe, Atomic Number 28

Oxygen

It is, by mass, the most common element in Earth's crust. It was discovered independently by Carl Scheele and Joseph Priestley; Priestley originally called it "dephlogisticated air." Atomic Symbol O, Atomic Number 8

Hydrogen

It naturally exists as a diatomic gas (H2), which was discovered by British chemist Henry Cavendish. ____________________ is highly flammable when exposed to high temperatures or electric current; a notable example of this was the Hindenburg disaster. Atomic Symbol H, Atomic Number 1

carbon

It occupies the same column in the periodic table as lead. Resistors which are commonly found in electronic circuits are often made out of this element. In addition, in one of its forms, this element is one of the hardest substances on earth.

Carbon

It's ability to form four chemical bonds means that it has many different allotropes. The best-characterized natural isotopes are diamond, which consists of a tetrahedral network of _______ atoms, and graphite, which consists of planes of _______ atoms arranged in hexagons. Atomic Symbol C, Atomic Number 6

Iron

Its isotope 56 is "doubly magic" in that its nucleus has 28 protons and 28 neutrons; 28 is a magic number that carries special stability. As a result, ____-56 is one of the most stable of all nuclei, and it is the heaviest nucleus that is normally produced during stellar nucleosynthesis. The largest use of ____ is in steel.

Gold

Known to the ancients as a relatively inert metal. Its atomic symbol Au comes from its Latin name, aurum. It is resistant to attack by most acids, but it (along with platinum) will dissolve in aqua regia, a mixture of concentrated nitric acid and hydrochloric acid. Atomic Symbol Au, Atomic Number 79

Conservation of Matter or Mass

Matter can be neither created nor destroyed, though it can be rearranged. Mass remains constant in an ordinary chemical change.

aluminum

Metallic elements are often obtained from ores. Name the metallic element which is produced from the ore Bauxite

LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CESIUM, AND FRANCIUM

Name the alkali metals.

uranium

Name the element discovered upon its extraction from pitchblende

Mercury

Older names for it, reflecting its liquid nature, include hydrargyrum (the source of its symbol) and quicksilver. Because it is a very dense liquid, it is commonly used in barometers to measure atmospheric pressure; the pressure exerted by the atmosphere equals the pressure exerted by a column containing 760 millimeters of ___________________. Atomic Symbol Hg, Atomic Number 80

Chalogens (Group 6A)

Part of the periodic table with nonmetals oxygen (O), sulfur (S), and selenium (Se), the metalloid tellurium (Te), and the metal polonium (Po)

Group 3A

Silvery in appearance, and like all metals are good conductors of electricity. They are relatively soft metals, with lower melting points than many of the Group 2A metals. includes the metalloid boron (B), as well as the metals aluminum (Al), gallium (Ga), indium (In), and thallium (Tl)

Radioactivity

Spontaneous emission of particles or high-energy electromagnetic radiation from the nuclei of unstable atoms.

Lead

The Betterton-Kroll process is used to remove bismuth from ores of this element, and the Parkes Process removes silver from this element as well.

alkali metals

The elements in group 1A of the periodic table are called:

Hydrogen

The first element on the periodic table and, by far, the most common element in the Universe. In addition to the main isotope (also called protium), there are two other significant isotopes of ______________________: deuterium (2H or D), which has one neutron, and tritium (3H or T), which has two neutrons. It can react with nonmetals by losing an electron to form the H+ ion, or react with metals to form the hydride ion H-. Atomic Symbol H, Atomic Number 1

Astatine (At)

The halogen with the largest atomic radius is:

Helium

The lightest noble gas and the second most abundant element in the Universe (after hydrogen). Discovered by Sir William Ramsey, Pierre Janssen, and Norman Lockyer, it has two stable isotopes, __________-3 and __________-4, with __________-4 by far the more common. Atomic Symbol He, Atomic Number 2

Aluminum

The most common metal in Earth's crust, and the first metal in the p block of elements. First isolated by Hans Christian Oersted, its primary ore is bauxite, from which it is refined using large amounts of electric current, via electrolysis, through the Bayer and Hall-Héroult processes. Atomic Symbol Al, Atomic Number 13

Group 5A

The nonmetals nitrogen (N), and phosphorus (P), the metalloids arsenic (As) and antimony (Sb), and the metal bismuth (Bi). Also called Pnictogens.

Atomic Number

The number of protons in a nucleus

Law of Definite Proportions

When two pure substances react to form a compound, they do so in a definite proportion by mass. For example, when water is formed from the reaction between hydrogen and oxygen, the 'definite proportion' is 1 g of H for every 8 g of O.

Radon

Which noble gas has the highest melting point?

James Chadwick

Who is accredited in the history of modern chemistry of proving that neutrons existed?

Sulfur

Widely known in the ancient world, and is referred to in the Bible as brimstone. Its nature as an element was first recognized by Antoine Lavoisier. Its most stable allotrope is an eight-membered ring that exists as a yellow solid. Atomic Symbol S, Atomic Number 16

Iron

_________ is the namesake of ferromagnetism; one of its ores is magnetite, Fe3O4, which contains iron in both of its most common oxidation states, 2+ and 3+. ______(II) sulfide, FeS2, is formally known as pyrite, but because of its appearance has long been known as fool's gold. Atomic Symbol Fe, Atomic Number 28

Helium

___________________ has the lowest boiling point of any element; liquid __________ is used for devices that need intense cooling, such as MRI machines. Most __________ on Earth results from radioactive decay, since the __________ nucleus is equivalent to an alpha particle. Atomic Symbol He, Atomic Number 2

Oxygen

___________________ normally exists in elemental form as a diatomic gas (O2), but it can also exist in a triatomic form, ozone (O3), which is known for its role in blocking UV rays in Earth's stratosphere. Atomic Symbol O, Atomic Number 8

Single Replacement Reaction (aka Single Displacement)

a type of oxidation-reduction chemical reaction when an element or ion moves out of one compound and into another - that is, one element is replaced by another in a compound.

Transition Metals

occupy the short columns in the center of the periodic table, between Group 2A and Group 3A. They are sometimes called the d-block elements, since in this region the d-orbitals are being filled in, and are also referred to as B-group elements

Avogadro's Number

the number of particles found in one mole of a substance. It is the number of atoms in exactly 12 grams of carbon-12. This experimentally determined value is approximately 6.0221 x 1023 particles per mol