Elements
Which major class of elements is shiny, malleable, and excellent at conducting heat and electricity?
Metals
Which Russian chemist created the first widely accepted periodic table and predicted undiscovered elements?
Dmitri Mendeleev
What is the dense, central region of an atom that contains protons and neutrons?
Nucleus
What is a pure substance that cannot be broken down into simpler substances by chemical means?
Element
What do you call the electrons in the outermost shell of an atom that are involved in forming chemical bonds?
Valence electrons
What is the name of the highly reactive Group 1 metals that react violently with water?
Alkali Metals
What are the horizontal rows on the periodic table called, which tell you the number of electron shells?
Periods
Which subatomic particle has a negative charge and orbits the nucleus?
Electron
What is a pure substance made of two or more different elements chemically combined in a fixed ratio?
Compound
What type of chemical bond is formed when a metal transfers electrons to a nonmetal?
lonic bond
What is the name of the highly reactive Group 17 nonmetals often used in disinfectants?
Halogens
What are the vertical columns on the periodic table called, which contain elements with similar chemical properties?
Groups
Atoms of the same element that have different numbers of neutrons are called what?
Isotopes
What do you call a combination of two or more substances that are physically blended together but not chemically bonded?
Mixture
What type of chemical bond is formed when two nonmetal atoms share electrons?
Covalent bond
Which elements have properties of both metals and nonmetals and are commonly used as semiconductors?
Metalloids
In the modern periodic table, elements are arranged in order of increasing what?
Atomic number
What do you call an atom that has gained or lost electrons, giving it an electric charge?
Ion
What type of mixture is so evenly blended that you cannot see the individual parts, like saltwater?
Homogeneous mixture
What scientific law states that matter cannot be created or destroyed in a chemical reaction?
Law of Conservation of Mass
What is the only metal element that exists as a liquid at room temperature?
Mercury
Which group of highly stable, unreactive gases is located in Group 18 on the far right of the periodic table?
Novel Gases
What is the name of the theory stating that electrons do not travel in perfect orbits, but instead exist in regions of probability called clouds?
Electron Cloud Model
What separation method is used to separate a solid from a liquid by passing the mixture through a porous barrier?
Filtration
What type of chemical reaction releases energy into its surroundings, usually in the form of heat or light?
Exothermic reaction