Chemistry Review - Atoms & Molecules Polar Attractions

Learning Objective

• Discuss the electronic and structural properties of an atom

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Key Points

• An atom is composed of two regions: the nucleus, which is in the eye of the atom and contains protons and neutrons, and the outer region of the atom, which holds its electrons in orbit effectually the nucleus.
• Protons and neutrons accept approximately the same mass, about 1.67 × ten-24 grams, which scientists define as ane atomic mass unit (amu) or one Dalton.
• Each electron has a negative charge (-ane) equal to the positive accuse of a proton (+ane).
• Neutrons are uncharged particles constitute within the nucleus.

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Terms

• protonPositively charged subatomic particle forming part of the nucleus of an atom and determining the atomic number of an chemical element. Information technology weighs 1 amu.
• atomThe smallest possible amount of matter which still retains its identity as a chemical element, consisting of a nucleus surrounded by electrons.
• neutronA subatomic particle forming part of the nucleus of an atom. Information technology has no charge. It is equal in mass to a proton or it weighs 1 amu.

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An atom is the smallest unit of matter that retains all of the chemic properties of an element. Atoms combine to grade molecules, which and then interact to form solids, gases, or liquids. For example, water is composed of hydrogen and oxygen atoms that have combined to class water molecules. Many biological processes are devoted to breaking downward molecules into their component atoms then they can be reassembled into a more than useful molecule.

Diminutive Particles

Atoms consist of three basic particles: protons, electrons, and neutrons. The nucleus (middle) of the cantlet 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 take unlike properties based on the arrangement and number of their basic particles.

The hydrogen atom (H) contains only i proton, one electron, and no neutrons. This tin be determined using the atomic number and the mass number of the element (see the concept on atomic numbers and mass numbers).

Structure of an atomElements, such every bit helium, depicted here, are made upward of atoms. Atoms are made up of protons and neutrons located inside the nucleus, with electrons in orbitals surrounding the nucleus.

Diminutive Mass

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 of measurement (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, merely not to its accuse.

Electrons are much smaller in mass than protons, weighing but ix.eleven × 10^-28 grams, or about ane/1800 of an atomic mass unit of measurement. Therefore, they practice not contribute much to an element's overall atomic mass. When considering diminutive mass, it is customary to ignore the mass of any electrons and calculate the atom'southward 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 "-one. " In an uncharged, neutral atom, the number of electrons orbiting the nucleus is equal to the number of protons within the nucleus. In these atoms, the positive and negative charges cancel each other out, leading to an cantlet with no net charge.

Protons, neutrons, and electronsBoth protons and neutrons have a mass of i amu and are found in the nucleus. All the same, protons have a charge of +one, and neutrons are uncharged. Electrons accept a mass of approximately 0 amu, orbit the nucleus, and have a charge of -ane.

Exploring Electron BackdropCompare the behavior of electrons to that of other charged particles to discover backdrop of electrons such every bit accuse and mass.

Volume of Atoms

Accounting for the sizes of protons, neutrons, and electrons, most of the volume of an atom—greater than 99 per centum—is, in fact, empty space. Despite all this empty infinite, solid objects do non only pass through 1 another. The electrons that environment all atoms are negatively charged and cause atoms to repel i another, preventing atoms from occupying the same space. These intermolecular forces prevent you from falling through an object similar your chair.

Interactive: Build an CantletBuild an cantlet out of protons, neutrons, and electrons, and see how the chemical element, charge, and mass change. And then play a game to test your ideas!

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Source: https://courses.lumenlearning.com/introchem/chapter/overview-of-atomic-structure/

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