Watching this resources will notify you when proposed changes or new versions are created so you can keep track of improvements that have been made.
Favoriting this resource allows you to save it in the “My Resources” tab of your account. There, you can easily access this resource later when you’re ready to customize it or assign it to your students.
Atoms are made up of particles called protons, neutrons, and electrons, which are responsible for the mass and charge of atoms.
Discriminate the three subatomic particles of an atom
Discuss the electronic and structural properties of an atom
An atom is composed of two regions: the nucleus, which is in the center of the atom and contains protons and neutrons, and the outer region of the atom, which holds its electrons in orbit around the nucleus.
Protons and neutrons have approximately the same mass, about 1.67 × 10-24 grams, which scientists define as one atomic mass unit (amu) or one Dalton.
Each electron has a negative charge (-1) equal to the positive charge of a proton (+1).
Neutrons are uncharged particles found within the nucleus.
An atom is the smallest unit of matter that retains all of the chemical properties of an element.
Atoms combine to form molecules, which then interact to form solids, gases, or liquids.
For example, water is composed of hydrogen and oxygen atoms that have combined to form water molecules.
Many biological processes are devoted to breaking down molecules into their component atoms so they can be reassembled into a more useful molecule.
Atoms consist of three basic particles: protons, electrons, and neutrons.
The nucleus (center) of the atom contains the protons (positively charged) and the neutrons (no charge).
The outermost regions of the atom are called electron shells and contain the electrons (negatively charged).
Atoms have different properties based on the arrangement and number of their basic particles.
The hydrogen atom (H) contains only one proton, one electron, and no neutrons.
This can be determined using the atomic number and the mass number of the element (see the concept on atomic numbers and mass numbers).
Protons and neutrons have approximately the same mass, about 1.67 × 10-24 grams.
Scientists define this amount of mass as one atomic mass unit (amu) or one Dalton.
Although similar in mass, protons are positively charged, while neutrons have no charge.
Therefore, the number of neutrons in an atom contributes significantly to its mass, but not to its charge.
Electrons are much smaller in mass than protons, weighing only 9.11 × 10-28 grams, or about 1/1800 of an atomic mass unit.
Therefore, they do not contribute much to an element's overall atomic mass.
When considering atomic mass, it is customary to ignore the mass of any electrons and calculate the atom's mass based on the number of protons and neutrons alone.
Electrons contribute greatly to the atom's charge, as each electron has a negative charge equal to the positive charge of a proton.
Scientists define these charges as "+1" and "-1.
" In an uncharged, neutral atom, the number of electrons orbiting the nucleus is equal to the number of protons inside the nucleus.
In these atoms, the positive and negative charges cancel each other out, leading to an atom with no net charge.
Accounting for the sizes of protons, neutrons, and electrons, most of the volume of an atom—greater than 99 percent—is, in fact, empty space.
Despite all this empty space, solid objects do not just pass through one another.
The electrons that surround all atoms are negatively charged and cause atoms to repel one another, preventing atoms from occupying the same space.
These intermolecular forces prevent you from falling through an object like your chair.
Protons and electrons weigh the same, neutrons weigh much less., Neutrons and electrons weigh the same, protons weigh much less., Protons, neutrons and electrons all weight the same., and Protons and neutrons weigh the same, electrons weigh much less.
Neutrons are positive, electrons are neutral, protons are negative., Electrons are positive, protons are neutral, neutrons are negative., Protons and neutrons have a charge of +1, while electrons have a much smaller charge., and Protons are positive, neutrons are neutral, electrons are negative.
The protons and electrons are in the nucleus, while the neutrons orbit the nucleus., The neutrons and electrons are in the nucleus, while the protons orbit the nucleus., The protons, neutrons and electrons are all in the nucleus., and The protons and neutrons are in the nucleus, while the electrons orbit the nucleus.