Vocab Unit 3 Flashcards
Atom
The smallest unit of an element that retains the chemical properties of that element.
Nucleus
The center of an atom, made of protons and neutrons.
Protons
Positively charged atomic particles weighing about 1 amu.
Neutrons
Neutrally charged atomic particles weighing about 1 amu.
Electrons
Negatively charged atomic particles weighing almost nothing- 1/1000 of an amu.
Element
A substance that cannot be broken down or separated into simpler substances by chemical means.
Molecule
Two or more atoms chemically bonded together.
Polar molecule
A molecule in which the distribution of electrons between the covalently bonded atoms is not even. For example, H2O is a polar molecule because the hydrogen atoms are positive and the oxygen atom is negative.
Energy level/electron cloud
The system of electrons that orbit the nucleus. Each level can hold a different number of electrons.
Atomic mass/weight
The number of protons and neutrons in the nucleus.
Covalent bond
Bond in which electrons between atoms are shared.
Ionic bond
Bond in which electrons are transferred from one atom to another, making one atom slightly positive and the other negative. The opposite charges attract.
Isotope
An atom with a differing number of neutrons, and therefore a differing atomic mass, that can release radiation.
Ion
An atom that gained or lost one or more electrons, giving it a slightly positive or negative charge.
Chemical reaction/equation
When chemical bonds break or form to change one substance into another.
Potential energy
Potential energy is defined as mechanical energy, stored energy, or energy caused by its position relative a zero position.
Kinetic energy
Energy from motion.
Chemical energy
The energy stored in chemical bonds between atoms and is released when the bonds are broken.
Activation energy
The minimum amount of energy required to start a chemical reaction.