Matter Vocabulary Flashcards
1
Q
atom
A
- definition: the smallest part of an element
- context: An atom is too small to see, so models are used to explain them.
2
Q
atomic number
A
- definition: the number of protons in the nucleus of each atom of an element
- context: On the periodic table, the elements are listed by atomic number.
3
Q
atomic mass
A
- definition: the mass of an element; nearly equal to the number of protons and neutrons found in the element’s nucleus
- context: The atomic mass of sodium is 22.990.
4
Q
chemical property
A
- definition: a characteristic of a substance that allows it to change to a new substance
- context: A chemical property of iron is that it reacts with oxygen in the air and produces rust.
5
Q
electron
A
- definition: an invisible, negatively charged particle that travels around the nucleus of an atom
- context: Electrons orbit the nucleus of an atom.
6
Q
electron cloud
A
- definition: the area surrounding the nucleus of an atom where electrons are likely to be found
- context: The electron cloud is made up of the atom’s electrons, and it travels in a space around the nucleus.
7
Q
electron dot diagram
A
- definition: the symbol for the element surrounded by as many dots as there are electrons in its outer energy level
- context: The number of electrons in an element’s outer energy level is shown by the electron dot diagram.
8
Q
element
A
- definition: a substance made up of only one kind of atom that cannot be divided by ordinary chemical means
- context: Gold is an element that cannot be broken down into any other substance by ordinary chemical means.
9
Q
energy level
A
- definition: the different positions and specific amount of an electron’s energy
- context: Energy level refers to the different areas of an atom where electrons are found.
10
Q
ion
A
- definition: an atom that has become electrically charged because it has gained or lost electrons
- context: A negative ion atom has more electrons than a positive ion atom.
11
Q
isotopes
A
- definition: atoms of the same element that have different numbers of neutrons but the same number of protons
- context: Atoms of all isotopes of carbon contain the same number of protons, but they do not have the same number of neutrons.
12
Q
mass number
A
- definition: the sum of the number of protons and neutrons in an atom of an element
- context: The number of protons plus the number of neutrons is an element’s mass number.
13
Q
matter
A
- definition: the term used to describe anything that has mass and takes up space
- context: Matter is made up of atoms.
14
Q
metal
A
- definition: an element that is malleable, ductile, a good conductor of electricity, and generally has a shiny or metallic luster
- context: Most elements are metals and, therefore, will conduct electricity.
15
Q
metalloid
A
- definition: an element that has characteristics of both metals and nonmetals and is solid at room temperature
- context: Silicon is a metalloid used to make electronic circuits.
16
Q
molecule
A
- definition: the smallest part of a compound that still has the properties of the compound
- context: Water is the most abundant molecule on Earth.
17
Q
neutron
A
- definition: an uncharged particle located in the nucleus of an atom
- context: The nucleus of an atom is made of two kinds of particles: positively charged protons and neutral neutrons.
18
Q
nonmetal
A
- definition: an element that is usually a gas or a brittle solid and is a poor conductor of electricity and heat
- context: The human body is mostly made up of nonmetals.
19
Q
nucleus
A
- definition: the positively charged, central part of an atom
- context: The nucleus of an atom is made of two kinds of particles: positively charged protons and neutral neutrons.
20
Q
periodic table
A
- definition: a chart that organizes the elements by the number of protons in each element’s nucleus
- context: A Periodic Table contains data about the elements.
21
Q
physical property
A
- definition: a characteristic of matter that can be observed, such as color, shape, smell, taste, texture, mass, volume, and density
- context: A physical property of clay is that it is malleable; squeezing it changes the shape.
22
Q
proton
A
- definition: a positively charged particle in the nucleus of an atom
- context: Protons are located in the nucleus of an atom.
23
Q
state of matter
A
- definition: the physical forms in which a substance can exist: solid, liquid, gas, and plasma
- context: Plasma represents the state of matter of the substances in the sun.
