The Surprising Elements With Multiple Aromatic Rings

Atoms are the smallest units of matter that retain the fundamental chemical properties of an element. An atom of sodium from table salt behaves differently from an atom of sodium from metallic sodium. This is because atoms of the same element can be in different states. For example, if one copper atom has an electron in an excited state and another copper atom has all its electrons in the ground state, the two atoms are different. The excited copper atom will emit light when the electron relaxes back down to the ground state, but the other will not. Atoms of the same element can also react differently if they are in different states. For instance, a neutral sodium atom reacts with water much more violently than an ionized sodium atom. Even if two atoms of the same element have electrons in the same state, they are still not identical. This is because they could be travelling or rotating at different speeds, which affects their ability to chemically bond. Additionally, atoms of the same element can have different numbers of neutrons and are referred to as isotopes. While isotopes do not affect how an atom will react chemically, they do determine how the atom will behave in nuclear reactions.

Atoms of the same element can have different numbers of neutrons in their nuclei

For example, 99% of carbon atoms have 6 neutrons and 6 protons in their nuclei, while about 1% of carbon atoms have 7 neutrons. Naturally occurring carbon on Earth is a mixture of these two isotopes. Another example is hydrogen, which usually has no neutrons in its nucleus. However, about 1 in 10,000 hydrogen atoms have one neutron, and this isotope is called deuterium. There is also a very rare isotope of hydrogen with two neutrons, called tritium.

Isotopes have different atomic masses due to their varying numbers of neutrons, but they exhibit similar chemical properties because they have the same number of protons and electrons. Most elements exist as a mixture of isotopes, and these isotopes can often be identified by their mass number, which is the sum of the number of protons and neutrons in the atom. For instance, carbon-12 has 6 neutrons (12-6=6), while carbon-13 has 7 neutrons (13-6=7).

The discovery of isotopes led to a refinement of Dalton's atomic theory, which initially proposed that all atoms of the same element were identical. However, it was later found that elements found in nature exist as mixtures of their naturally occurring isotopes.

Two atoms of the same element can be different if their electrons are in different states

Atoms of the same element are typically not identical. While they always have the same number of protons, the number of neutrons and electrons may differ. Atoms of the same element can have different numbers of neutrons in their nuclei, known as isotopes of the element.

There is a range of possible states that the electrons of an atom can occupy. Two atoms of the same element can be different if their electrons are in different states. If one copper atom has an electron in an excited state and another copper atom has all of its electrons in the ground state, then the two atoms are different. The excited copper atom will emit a bit of light when the electron relaxes back down to the ground state, and the copper atom already in the ground state will not. Since the states of the electrons in an atom are what determine the nature of the chemical bonding that the atom experiences, two atoms of the same element can react differently if they are in different states.

Even if two atoms of the same element have their electrons in the same state, they can still be different. They could be traveling or rotating at different speeds, which affects their ability to chemically bond. Slower-moving atoms (such as those in solid iron) have time to form stable bonds, while faster-moving atoms (such as those in liquid iron) cannot form such stable bonds.

The states of the electrons in an atom determine the nature of the chemical bonding

The outermost shell of an atom, called the valence shell, contains the electrons that are involved in bond formation. This is because they are the least tightly bound to the nucleus and can be removed most readily. The valence shell of noble gases is complete with its full complement of eight electrons. The formation of chemical bonds appears to be related to the incompleteness of the valence shell.

In the simplest view of a covalent bond, one or more electrons are drawn into the space between the two atomic nuclei. Energy is released by bond formation, not as a result of a reduction in potential energy, but due to the reduction in kinetic energy as the electrons are in a more spatially distributed orbital compared to when each electron is confined closer to its respective nucleus. Covalent bonds often result in the formation of small collections of better-connected atoms called molecules, which in solids and liquids are bound to other molecules by forces that are often much weaker than the covalent bonds that hold the molecules internally together.

In a simplified view of an ionic bond, the bonding electron is not shared at all but is transferred. In this type of bond, the outer atomic orbital of one atom has a vacancy that allows the addition of one or more electrons. These newly added electrons potentially occupy a lower energy state than they experience in a different atom. Thus, one nucleus offers a more tightly bound position to an electron than another nucleus, resulting in the transfer of an electron from one atom to the other. This transfer causes one atom to assume a net positive charge and the other a net negative charge. The bond then results from the electrostatic attraction between the positively and negatively charged ions. Ionic bonds are strong but also brittle, since the forces between ions are short-range and do not easily bridge cracks and fractures.

A less often mentioned type of bonding is metallic bonding. In this type of bonding, each atom in a metal donates one or more electrons to a "sea" of electrons that reside between many metal atoms. In this sea, each electron is free to be associated with a great many atoms at once. The bond results because the metal atoms become somewhat positively charged due to the loss of their electrons while the electrons remain attracted to many atoms without being part of any given atom. Metallic bonding may be seen as an extreme example of delocalization of electrons over a large system of covalent bonds, in which every atom participates. This type of bonding is often very strong, resulting in the tensile strength of metals. However, metallic bonding is more collective in nature than other types, allowing metal crystals to more easily deform. The cloud of electrons in metallic bonding causes the characteristically good electrical and thermal conductivity of metals, as well as their shiny lustre that reflects most frequencies of white light.

Atoms of the same element can react differently if they are in different states

Even if two atoms of the same element have electrons in the same states, they can still behave differently. This is because they could be travelling or rotating at different speeds, which affects their ability to chemically bond. Slower-moving atoms, such as those in solid iron, have time to form stable bonds, while faster-moving atoms, such as those in liquid iron, cannot form such stable bonds.

Even if two atoms of the same element are in the same electronic state and are travelling at the same speed, they can still be different. This is because there is more to the atom than the electrons—there is also the nucleus. The nucleus of an atom contains neutrons and protons bonded together, and even if the number of neutrons is the same, the protons and neutrons can be in various excited states. Therefore, two gold atoms, for example, can have their nuclei in different excited states and behave differently in nuclear reactions.

In summary, it is very hard to have two atoms of the same element be exactly identical.

The same chemical element can have a different number of neutrons and still be the same element

The number of protons in an atom determines its chemical identity. This is because the number of protons in an atom determines the number of electrons, which in turn determines the atom's chemical properties. Therefore, atoms with the same number of protons are the same element.

However, atoms of the same element can have a different number of neutrons. Atoms of the same element that have different numbers of neutrons are called isotopes. For example, all carbon atoms have 6 protons, but some have 6 neutrons, while others have 7 or 8. These are referred to as carbon-12, carbon-13, and carbon-14, respectively.

Isotopes of a given element have different masses but similar chemical properties. This is because, while the number of neutrons affects the mass of an atom, it usually has very little effect on its chemical properties.

Frequently asked questions