If an atom contains one electron

• Atoms are made of protons, neutrons, and electrons. • Protons carry a positive electrical change, while electrons are negatively charged, and neutrons are neutral. • A neutral atom has the same number of protons and electrons (charges cancel each other out). • An ion has an unequal number of protons and electrons. If the charge is positive, there are more protons than electrons. If the charge is negative, electrons are in excess. • You can find the number of neutrons if you know the isotope of the atom. Simply subtract the number of protons (the atomic number) from the mass number to find the remaining neutrons. Get Basic Information About Elements You'll need to gather basic information about the elements to find the number of protons, neutrons, and electrons. Fortunately, all you need is a Find the Number of Protons Each element is defined by the number of protons found in each of its atoms. No matter how many electrons or neutrons an atom has, the element is defined by its number of protons. In fact, it's actually possible to have an atom consisting of only a proton (ionized hydrogen). The periodic table is arranged in order of increasing If you are given the atomic weight of an atom, you need to subtract the number of neutrons to get the number of protons. Sometimes you can tell the elemental identity of a sample if all you have is the atomic weight. For example, if you have a sample with an atomic weight of 2, you can be pretty certain the element is hydrogen. Why? ...

Learning Objectives • Describe the locations, charges, and masses of the three main subatomic particles. • Determine the number of protons and electrons in an atom. • Define atomic mass unit (amu). Dalton's Atomic Theory explained a lot about matter, chemicals, and chemical reactions. Nevertheless, it was not entirely accurate, because contrary to what Dalton believed, atoms can, in fact, be broken apart into smaller subunits or subatomic particles. We have been talking about the electron in great detail, but there are two other particles of interest to us: protons and neutrons. We already learned that J. J. Thomson discovered a negatively charged particle, called the electron. Rutherford proposed that these electrons orbit a positive nucleus. In subsequent experiments, he found that there is a smaller positively charged particle in the nucleus, called a proton. There is also a third subatomic particle, known as a neutron. Neutrons Atoms of all elements—except for most atoms of hydrogen—have neutrons in their nucleus. Unlike protons and electrons, which are electrically charged, neutrons have no charge—they are electrically neutral. That's why the neutrons in the diagram above are labeled \(n^0\). The zero stands for "zero charge". The mass of a neutron is slightly greater than the mass of a proton, which is 1 atomic mass unit \(\left( \text\)) are useful, because, as you can see, the mass of a proton and the mass of a neutron are almost exactly \(1\) in this unit system. ...

\( \newcommand\) • • • • • • • • • • Learning Objectives • To know the meaning of isotopes and atomic masses. To date, about 118 different elements have been discovered; by definition, each is chemically unique. To understand why they are unique, you need to understand the structure of the atom (the fundamental, individual particle of an element) and the characteristics of its components. Atoms consist of electrons, protons, and neutrons. Although this is an oversimplification that ignores the other subatomic particles that have been discovered, it is sufficient for discussion of chemical principles. Some properties of these subatomic particles are summarized in Table \(\PageIndex\): The structure of helium atom with a central nucleus and surrounding electrons. (CC BY-SA 3.0; The Number of Protons Define the Nature of the Elements The number of protons in the nucleus of an atom is its atomic number (\(Z\)). This is the defining trait of an element: Its value determines the identity of the atom. For example, any atom that contains six protons is the element carbon and has the atomic number 6, regardless of how many neutrons or electrons it may have. A neutral atom must contain the same number of positive and negative charges, so the number of protons equals the number of electrons. Therefore, the atomic number also indicates the number of electrons in an atom. The total number of protons and neutrons in an atom is called its mass number (\(A\))). The number of neutrons is t...

• العربية • Asturianu • Беларуская • Български • Bosanski • Català • Чӑвашла • Dansk • Deutsch • Eesti • Español • Esperanto • فارسی • Français • Gaeilge • 한국어 • Hrvatski • Bahasa Indonesia • Italiano • עברית • Қазақша • Kreyòl ayisyen • Македонски • Nederlands • 日本語 • Norsk nynorsk • ਪੰਜਾਬੀ • Polski • Português • Română • Русский • Simple English • Slovenščina • Српски / srpski • Srpskohrvatski / српскохрватски • Svenska • தமிழ் • ไทย • Türkçe • Українська • 中文 • v • t • e A energy levels. This contrasts with In 1 shell" (also called "K shell"), followed by the " 2 shell" (or "L shell"), then the " 3 shell" (or "M shell"), and so on farther and farther from the nucleus. The shells correspond with the n = 1, 2, 3, 4...) or are labeled alphabetically with letters used in the Each shell can contain only a fixed number of electrons: The first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on. The general formula is that the nth shell can in principle hold up to 2 n 2 electrons. If the If an atom, ion, or molecule is at the lowest possible energy level, it and its electrons are said to be in the excited. An energy level is regarded as Explanation [ ] Quantized energy levels result from the wave behavior of particles, which gives a relationship between a particle's energy and its Any History [ ] The first evidence of quantization in atoms was the observation of Atoms [ ] Intrinsi...

There isn't any set number of isotopes an atom can have. As the number of neutrons in an atom increases or decreases, the isotopes tend to become more and more unstable until they get to the point where they decay faster than neutrons can change. According to the International Atomic Energy Agency, Mercury currently has the most at 45 identified isotopes. Every atom is made up of protons (that are positively charged), neutrons (that have no charge) and electrons (that have a negative charge). When we look at an atom, we find that it has the same about of protons as it does electrons. So, if we look at oxygen, we see that its atomic number is 8, meaning that it has 8 protons. We can also assume that it has 8 electrons. So, oxygen has eight positive particles plus eight negative particles. Think of this as 8+(-8) or 8-8. Eight minus eight equals zero, which is neutral. Basically, a "neutral atom" is an atom that has the same amount of protons as it does electrons. Later you will learn about ions, which have unequal amounts of protons and electrons. if protium [hydrogen w/ no neutrons] has the mass [weight] of only the single proton, and protons and neutrons have the same mass [weight], does that mean that deuterium is twice as massive [heavy] as protium? the same question would apply regarding tritium since it has only one proton but two neutrons. if so then since water generally weighs about six pounds / gallon, does that mean a gallon of deuterium would weigh about twelve ...

\( \newcommand\) • • • • Learning Objectives • Define the two types of ions. Most atoms do not have eight electrons in their valence electron shell. Some atoms have only a few electrons in their outer shell, while some atoms lack only one or two electrons to have an octet. In cases where an atom has three or fewer valence electrons, the atom may lose those valence electrons quite easily until what remains is a lower shell that contains an octet. Atoms that lose electrons acquire a positive charge as a result because they are left with fewer negatively charged electrons to balance the positive charges of the protons in the nucleus. Positively charged ions are called cations. Most metals become cations when they make ionic compounds. Cations A neutral sodium atom is likely to achieve an octet in its outermost shell by losing its one valence electron. \[\ce\): The Formation of a Sodium Ion. On the left, a sodium atom has 11 electrons. On the right, the sodium ion only has 10 electrons and a 1+ charge. Neutral sodium atom on left has 11 protons and 11 electrons. Sodium ion on right has 11 protons and 10 electrons, with a +1 overall charge. Anions Some atoms have nearly eight electrons in their valence shell and can gain additional valence electrons until they have an octet. When these atoms gain electrons, they acquire a negative charge because they now possess more electrons than protons. Negatively charged ions are called anions. Most nonmetals become anions when they make i...