Lesson 1
a mixture in which substances are evenly distributed throughout the mixture; solution
What is a homogeneous mixture?
uncharged particle in the nucleus of an atom
What is a neutron?
a positively charged particle and that is found in the nucleus of an atom
What is a proton?
anything that has mass and takes up space
What is matter?
center of an atom; contains neutrons and protons; most of the mass of an atom
What is a nucleus?
2 classifications of matter
What are substances and mixtures?
a region around the nucleus of an atom where one or more electrons are likely to be found
What is an electron cloud?
2 types of substances
What are elements and compounds?
a small particle that is a building block of matter
What is an atom?
a negatively charged particle that occupies the space in an atom outside the nucleus
What is an electron?
2 types of mixtures
What are homogeneous and heterogeneous mixtures?
an elements number of ___________ is always the same
What are protons?
a mixture in which substances are not evenly mixed
What is a heterogeneous mixture?
two or more atoms held together by chemical bonds and act as a unit
What is a molecule?
the number of protons in the nucleus of an atom of an element
What is the atomic number?
another name for a homogeneous mixture
What is a solution?
Sodium-23 is an example of an _________
What is an isotope?
Adding or losing a proton results in a new __________
What is element?
a substance made of only one kind of atom, some are diatomic like hydrogen and oxygen
What is an element?
Atoms of the same element that have different numbers of neutrons
What are isotopes?
a way to represent a compound using the symbols for the elements that are combined in the compound and numbers; H2O
What is a chemical formula?
each element has different characteristics because of the ___________ of tiny particles inside its atoms
What are numbers?
Name a way to separate a homogeneous mixture.
What is boiling or evaporating?
matter that can vary in composition; contains substances that are not chemically combined
What are mixtures?
an atom that has a charge because it has gained or lost one or more electrons
What are ions?