What Do You Need to Know to Diagram an Atom

Overview of Atomic Structure

Atoms are made upwardly of particles called protons, neutrons, and electrons, which are responsible for the mass and charge of atoms.

Learning Objectives

Discuss the electronic and structural backdrop of an atom

Key Takeaways

Key Points

• An atom is equanimous of two regions: the nucleus, which is in the center of the cantlet and contains protons and neutrons, and the outer region of the cantlet, which holds its electrons in orbit around the nucleus.
• Protons and neutrons have approximately the same mass, most 1.67 × 10-24 grams, which scientists define as one diminutive mass unit (amu) or one Dalton.
• Each electron has a negative charge (-1) equal to the positive accuse of a proton (+i).
• Neutrons are uncharged particles found within the nucleus.

Key Terms

• atom: The smallest possible corporeality of matter which still retains its identity as a chemical element, consisting of a nucleus surrounded by electrons.
• proton: Positively charged subatomic particle forming part of the nucleus of an cantlet and determining the diminutive number of an chemical element. Information technology weighs 1 amu.
• neutron: A subatomic particle forming part of the nucleus of an atom. It has no charge. Information technology is equal in mass to a proton or it weighs 1 amu.

An atom is the smallest unit of matter that retains all of the chemic properties of an element. Atoms combine to course molecules, which and so interact to grade solids, gases, or liquids. For example, water is composed of hydrogen and oxygen atoms that have combined to form h2o molecules. Many biological processes are devoted to breaking downwards molecules into their component atoms so they can exist reassembled into a more useful molecule.

Atomic Particles

Atoms consist of iii basic particles: protons, electrons, and neutrons. The nucleus (middle) of the atom contains the protons (positively charged) and the neutrons (no charge). The outermost regions of the cantlet are called electron shells and contain the electrons (negatively charged). Atoms accept different properties based on the organisation and number of their basic particles.

The hydrogen cantlet (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).

Structure of an atom: Elements, such as helium, depicted here, are made up of atoms. Atoms are fabricated upwardly of protons and neutrons located within the nucleus, with electrons in orbitals surrounding the nucleus.

Atomic Mass

Protons and neutrons have approximately the same mass, almost ane.67 × ten^-24 grams. Scientists define this amount of mass equally one atomic mass unit of measurement (amu) or one Dalton. Although similar in mass, protons are positively charged, while neutrons have no accuse. Therefore, the number of neutrons in an atom contributes significantly to its mass, but non to its charge.

Electrons are much smaller in mass than protons, weighing simply ix.11 × ten^-28 grams, or about 1/1800 of an diminutive mass unit. Therefore, they practise not contribute much to an element's overall atomic mass. When because atomic mass, it is customary to ignore the mass of any electrons and calculate the atom'due south mass based on the number of protons and neutrons lonely.

Electrons contribute greatly to the atom's accuse, equally each electron has a negative charge equal to the positive charge of a proton. Scientists ascertain these charges as "+i" and "-1. " In an uncharged, neutral cantlet, 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.

Protons, neutrons, and electrons: Both protons and neutrons have a mass of one amu and are plant in the nucleus. However, protons have a accuse of +1, and neutrons are uncharged. Electrons have a mass of approximately 0 amu, orbit the nucleus, and have a charge of -ane.

Exploring Electron Properties: Compare the beliefs of electrons to that of other charged particles to discover backdrop of electrons such as accuse and mass.

Book of Atoms

Bookkeeping for the sizes of protons, neutrons, and electrons, most of the book of an atom—greater than 99 percent—is, in fact, empty infinite. Despite all this empty space, solid objects do not just pass through ane another. The electrons that environment all atoms are negatively charged and cause atoms to repel one some other, preventing atoms from occupying the same infinite. These intermolecular forces forestall you from falling through an object similar your chair.

Interactive: Build an Atom: Build an atom out of protons, neutrons, and electrons, and see how the element, charge, and mass change. Then play a game to examination your ideas!

Atomic Number and Mass Number

The atomic number is the number of protons in an chemical element, while the mass number is the number of protons plus the number of neutrons.

Learning Objectives

Determine the human relationship betwixt the mass number of an atom, its atomic number, its atomic mass, and its number of subatomic particles

Key Takeaways

Key Points

• Neutral atoms of each element contain an equal number of protons and electrons.
• The number of protons determines an element'due south atomic number and is used to distinguish ane element from another.
• The number of neutrons is variable, resulting in isotopes, which are different forms of the same atom that vary simply in the number of neutrons they possess.
• Together, the number of protons and the number of neutrons make up one's mind an element's mass number.
• Since an element's isotopes have slightly different mass numbers, the diminutive mass is calculated past obtaining the mean of the mass numbers for its isotopes.

Key Terms

• mass number: The sum of the number of protons and the number of neutrons in an cantlet.
• atomic number: The number of protons in an cantlet.
• atomic mass: The boilerplate mass of an atom, taking into account all its naturally occurring isotopes.

Atomic Number

Neutral atoms of an chemical element contain an equal number of protons and electrons. The number of protons determines an element'south atomic number (Z) and distinguishes one element from another. For instance, carbon's atomic number (Z) is 6 because information technology has vi protons. The number of neutrons tin can vary to produce isotopes, which are atoms of the same chemical element that take unlike numbers of neutrons. The number of electrons tin can also be different in atoms of the aforementioned element, thus producing ions (charged atoms). For instance, iron, Fe, tin be in its neutral state, or in the +2 and +3  ionic states.

Mass Number

An element'due south mass number (A) is the sum of the number of protons and the number of neutrons. The small-scale contribution of mass from electrons is disregarded in calculating the mass number. This approximation of mass can be used to easily calculate how many neutrons an element has past simply subtracting the number of protons from the mass number. Protons and neutrons both counterbalance well-nigh one atomic mass unit of measurement or amu. Isotopes of the same element will have the same diminutive number but unlike mass numbers.

Atomic number, chemic symbol, and mass number: Carbon has an atomic number of six, and two stable isotopes with mass numbers of twelve and thirteen, respectively. Its boilerplate atomic mass is 12.11.

Scientists make up one's mind the atomic mass past calculating the hateful of the mass numbers for its naturally-occurring isotopes. Oftentimes, the resulting number contains a decimal. For instance, the atomic mass of chlorine (Cl) is 35.45 amu considering chlorine is composed of several isotopes, some (the majority) with an diminutive mass of 35 amu (17 protons and eighteen neutrons) and some with an atomic mass of 37 amu (17 protons and 20 neutrons).

Given an atomic number (Z) and mass number (A), you can find the number of protons, neutrons, and electrons in a neutral atom. For case, a lithium cantlet (Z=three, A=vii amu) contains three protons (found from Z), three electrons (every bit the number of protons is equal to the number of electrons in an atom), and four neutrons (vii – 3 = iv).

Isotopes

Isotopes are various forms of an element that have the same number of protons, merely a different number of neutrons.

Learning Objectives

Discuss the backdrop of isotopes and their utilize in radiometric dating

Key Takeaways

Central Points

• Isotopes are atoms of the same element that comprise an identical number of protons, just a unlike number of neutrons.
• Despite having different numbers of neutrons, isotopes of the aforementioned chemical element take very like physical properties.
• Some isotopes are unstable and will undergo radioactive decay to become other elements.
• The predictable half-life of unlike decaying isotopes allows scientists to date fabric based on its isotopic composition, such as with Carbon-14 dating.

Key Terms

• isotope: Any of two or more than forms of an element where the atoms have the same number of protons, but a dissimilar number of neutrons within their nuclei.
• one-half-life: The time it takes for half of the original concentration of an isotope to decay dorsum to its more stable grade.
• radioactive isotopes: an atom with an unstable nucleus, characterized past excess energy available that undergoes radioactive decay and creates almost ordinarily gamma rays, alpha or beta particles.
• radiocarbon dating: Determining the age of an object by comparison the ratio of the 14C concentration found in information technology to the corporeality of 14C in the atmosphere.

What is an Isotope?

Isotopes are various forms of an element that have the same number of protons but a different number of neutrons. Some elements, such as carbon, potassium, and uranium, have multiple naturally-occurring isotopes. Isotopes are defined starting time by their chemical element and and then by the sum of the protons and neutrons nowadays.

• Carbon-12 (or ¹²C) contains vi protons, six neutrons, and six electrons; therefore, it has a mass number of 12 amu (vi protons and half dozen neutrons).
• Carbon-14 (or ^fourteenC) contains 6 protons, eight neutrons, and half dozen electrons; its atomic mass is fourteen amu (six protons and viii neutrons).

While the mass of individual isotopes is different, their physical and chemical properties remain mostly unchanged.

Isotopes do differ in their stability. Carbon-12 (¹²C) is the nigh arable of the carbon isotopes, accounting for 98.89% of carbon on Earth. Carbon-14 (^xivC) is unstable and only occurs in trace amounts. Unstable isotopes nearly commonly emit blastoff particles (He^two+) and electrons. Neutrons, protons, and positrons tin can also exist emitted and electrons can exist captured to attain a more stable atomic configuration (lower level of potential free energy ) through a process chosen radioactive decay. The new atoms created may be in a high energy state and emit gamma rays which lowers the free energy but alone does not modify the atom into another isotope. These atoms are chosen radioactive isotopes or radioisotopes.

Radiocarbon Dating

Carbon is normally nowadays in the atmosphere in the form of gaseous compounds like carbon dioxide and methane. Carbon-fourteen (¹⁴C) is a naturally-occurring radioisotope that is created from atmospheric ^fourteenDue north (nitrogen) by the addition of a neutron and the loss of a proton, which is caused by cosmic rays. This is a continuous procedure so more than ¹⁴C is ever being created in the atmosphere. In one case produced, the ^xivC often combines with the oxygen in the atmosphere to form carbon dioxide. Carbon dioxide produced in this way diffuses in the atmosphere, is dissolved in the ocean, and is incorporated by plants via photosynthesis. Animals eat the plants and, ultimately, the radiocarbon is distributed throughout the biosphere.

In living organisms, the relative amount of ¹⁴C in their body is approximately equal to the concentration of ¹⁴C in the atmosphere. When an organism dies, it is no longer ingesting ¹⁴C, so the ratio between ¹⁴C and ¹²C will decline every bit ¹⁴C gradually decays back to ¹⁴N. This boring process, which is called beta decay, releases energy through the emission of electrons from the nucleus or positrons.

After approximately 5,730 years, half of the starting concentration of ¹⁴C will take been converted back to ¹⁴N. This is referred to every bit its half-life, or the time it takes for half of the original concentration of an isotope to decay back to its more stable form. Because the one-half-life of ^fourteenC is long, it is used to date formerly-living objects such as old basic or wood. Comparing the ratio of the ¹⁴C concentration found in an object to the corporeality of ¹⁴C in the atmosphere, the corporeality of the isotope that has not nevertheless decayed can be determined. On the basis of this amount, the age of the material can be accurately calculated, as long as the textile is believed to be less than 50,000 years old. This technique is chosen radiocarbon dating, or carbon dating for brusque.

Application of carbon dating: The age of carbon-containing remains less than 50,000 years old, such as this pygmy mammoth, tin exist determined using carbon dating.

Other elements take isotopes with different one-half lives. For example, ^xlK (potassium-40) has a half-life of 1.25 billion years, and ²³⁵U (uranium-235) has a half-life of about 700 meg years. Scientists often apply these other radioactive elements to date objects that are older than l,000 years (the limit of carbon dating). Through the use of radiometric dating, scientists can study the age of fossils or other remains of extinct organisms.

williamstentsman65.blogspot.com

Source: https://courses.lumenlearning.com/boundless-chemistry/chapter/the-structure-of-the-atom/

Share this post