Chapter 3 Review

Physical mixture in which substances are physically combined and are evenly mixed

What identifies the number of protons + the number of neutrons an atom contains?

invisible, negatively charged particles that orbit the nucleus.

Physical mixture in which substances are physically combined but not evenly mixed

elements that are usually dull in appearance, poor conductors of heat and electricity, and many are gases at room temp

elements where some are shiny and good conductors while others are dull and poor conductors. All solid at room temp

the smallest unit or particle of matter.

created the atomic theory of matter through the atomic model.

elements that can be naturally found such as oxygen, nitrogen, iron, copper, or gold

Discovered the electron and pioneered the cathode ray experiment

found evidence that atoms are organized according to energy level.

Discovered that atoms possess a nucleus through his gold foil alpha particle experiments

What represents the chemical symbol?

Discovered neutrons after observing that the atom was too heavy to contain only protons and electrons

Positively charged particles inside the nucleus

elements made in nuclear reactions by scientists.

What are atoms of the same element that have different numbers of neutrons called?

uncharged particles inside the nucleus

The weighted average of the isotopes of an element. Found at the bottom of the element symbol.

What represents the mass number

Anything that takes up space and has mass

What forms a chemical shorthand to save scientists time on the periodic table and in chemical equations and formulas?

What reperesents the atomic number

Two or more elements that are chemically combined

individual discrete atoms

elements composed of molecules made up of 2 same atoms that are bonded together

The positively charged, central part of the atom.

Simplest form of matter from which more complex substances are made