118 Elements and Their Symbols and Atomic Numbers

There are 118 elements in the periodic table. The first element of the periodic table is Hydrogen, and the last element is Oganesson.  

Symbols of some elements are derived from their Greek names. For example, the Latin name of gold is ‘aurum’, that why the symbol of gold is ‘Au’. In the same way, the symbol of sodium is ‘Na’ because it is derived from its Latin name ‘natrium’.  

There are 118 elements in the periodic table, out of which many elements occur naturally, like Oxygen, carbon, iron, etc, while elements with high atomic numbers, like those whose atomic number is greater than 92, are synthesized in laboratories and nuclear reactors.

Noble gases like Helium, Neon, Argon, Krypton, Xenon, and Radon are generally inert, which means they do not react easily with other elements. This is due to their fully valence electron shells, which make them stable.    

Ununennium, also known as eka-francium or element 119. As of August 2025, element 119, known as Ununennium (Uue), has not been confirmed.

Yes, element 118 is a real element, and it is known as Oganesson (Og). It was named in honor of Russian physicist Yuri Oganessian, who contributed significantly to the discovery of superheavy elements.

An element's atomic number is determined by the number of protons in its nucleus. It's crucial because it defines the element's identity and determines its position in the periodic table. Elements with different atomic numbers are different elements, regardless of their isotopes or ionic forms.

The atomic number determines the number of electrons in a neutral atom of that element. This, in turn, dictates the element's electron configuration, which is crucial in determining its chemical properties and behavior.

The atomic number is the number of protons, while the mass number is the total number of protons and neutrons. The difference between these numbers gives the number of neutrons. This relationship is crucial for understanding isotopes.

Isotopes of an element have the same atomic number (same number of protons) but different mass numbers (different numbers of neutrons). This means isotopes have identical chemical properties but can have different physical properties, like radioactivity.

Noble gases (atomic numbers 2, 10, 18, 36, 54, 86) have full outer electron shells, making them extremely stable and unreactive. Their atomic numbers correspond to complete electron shell fillings, which is key to understanding electron configuration patterns.

Elements in the periodic table are arranged in order of increasing atomic number. This arrangement reveals periodic trends in element properties, as elements in the same column (group) have similar electron configurations and chemical behaviors.

Element 118, Oganesson, is currently the heaviest known element and the last one in the 7th period of the periodic table. It's significant because it completes the p-block of the periodic table and is the last element that can be placed using the current table structure.

The symbol quickly identifies the element, while the atomic number provides information about its structure (number of protons and electrons). Together, they allow chemists to predict the element's behavior, its position in the periodic table, and its relationships with other elements.

Lanthanides (atomic numbers 57-71) and actinides (89-103) are placed separately for convenience, as including them in the main table would make it too wide. They have similar properties within each series due to their f-orbital electron configurations.

Transition metals and main group elements don't differ in how their symbols and atomic numbers are assigned. However, transition metals, located in the d-block, have atomic numbers 21-30, 39-48, 57-80, and 89-112, and often use electrons from multiple shells in bonding.

Elements have symbols as shorthand representations for easier communication in chemistry. They are typically derived from the element's name in English or other languages, often using the first one or two letters. For example, 'H' for Hydrogen, 'He' for Helium, and 'Na' (from Latin 'Natrium') for Sodium.

Some elements have symbols derived from their Latin or Greek names, or historical names. For instance, 'Au' for Gold (from Latin 'Aurum'), 'K' for Potassium (from Latin 'Kalium'), and 'W' for Tungsten (from German 'Wolfram').

Single-letter symbols are used for the first 26 elements discovered or commonly known. Two-letter symbols are used for subsequent elements to avoid duplication. The first letter is always capitalized, while the second is lowercase.

New elements are typically named by their discoverers, subject to approval by the International Union of Pure and Applied Chemistry (IUPAC). Temporary systematic element names and symbols based on their atomic numbers are used until an official name is approved.

Atomic numbers determine the total number of electrons, which dictates the electron configuration. Valence electrons, the outermost electrons involved in bonding, can often be predicted from an element's group number in the periodic table.

Atomic numbers determine electron configurations, which in turn influence reactivity. Elements with similar outer electron configurations (same group) tend to have similar reactivities. For example, alkali metals (Group 1) are highly reactive due to their single outer electron.

Hydrogen (atomic number 1) is placed alone because it behaves differently from other elements. Helium (atomic number 2) is placed with noble gases due to its full outer shell, despite having a different electron configuration from other noble gases.

Lead-82 is the heaviest stable element. Elements with higher atomic numbers are all radioactive. This relates to the concept of nuclear stability and the neutron-to-proton ratio needed for stable nuclei.

The periodic law states that element properties are periodic functions of their atomic numbers. This means elements with similar properties appear at regular intervals when arranged by atomic number, forming the basis of the periodic table's structure.

Multiple oxidation states often occur in elements with partially filled d or f orbitals. The atomic number determines the electron configuration, which in turn influences the possible oxidation states. Transition metals, with their variable d-orbital occupancy, often exhibit multiple oxidation states.

Atomic number determines the nuclear charge. Effective nuclear charge is the net positive charge experienced by an electron, considering the shielding effect of inner electrons. It generally increases across a period and decreases down a group.

Electronegativity generally increases with atomic number across a period (due to increasing effective nuclear charge) and decreases down a group (due to increasing atomic radius). This trend is directly related to the electron configuration determined by the atomic number.

Isoelectronic species have the same number of electrons but different atomic numbers. Understanding atomic numbers helps identify such species, as the number of electrons in an ion can be calculated by subtracting (for cations) or adding (for anions) to the atomic number.

Gaps in the sequence of atomic numbers for naturally occurring elements exist because some elements are synthetic and do not occur in nature. These elements, typically with high atomic numbers, are created in laboratories through nuclear reactions.

Electron affinity generally increases across a period and decreases down a group, following trends similar to electronegativity. This is because atomic number determines electron configuration, which influences how easily an atom can accept an additional electron.

Uranium (atomic number 92) is the highest atomic numbered element found in significant quantities in nature. All elements with higher atomic numbers are either synthetic or found only in trace amounts in nature, marking a transition in the periodic table.

Ionization energy generally increases across a period and decreases down a group. This trend is directly related to the electron configuration and effective nuclear charge, both determined by the atomic number.

Elements in the same group have similar outer electron configurations, despite different atomic numbers. This similarity in valence electrons leads to similar chemical properties, illustrating the periodic nature of element properties.

Atomic radius generally decreases across a period and increases down a group. This trend is due to the increasing nuclear charge (determined by atomic number) across a period and the addition of new electron shells down a group.

Iron-56 (with 26 protons and 30 neutrons) has the highest binding energy per nucleon of any nucleus. This makes it the most stable nucleus, which is significant in understanding nuclear reactions and the formation of elements in stars.

Atomic numbers determine electron configurations, which influence magnetic properties. Elements with unpaired electrons (often transition metals) are paramagnetic or ferromagnetic, while those with paired electrons are diamagnetic.

Fractional atomic weights result from the natural occurrence of multiple isotopes of an element. While the atomic number (number of protons) is always a whole number, the average mass of an element's isotopes can be fractional.

Metallic character generally decreases across a period and increases down a group. This trend is related to the ease of losing electrons, which is influenced by the electron configuration and effective nuclear charge, both determined by the atomic number.

Tin, with atomic number 50, sits at the border between metals and metalloids on the periodic table. It exhibits properties of both, illustrating how atomic number influences an element's position and properties in the periodic table.

Each element has a unique atomic emission spectrum due to its specific electron configuration, which is determined by its atomic number. When excited electrons return to lower energy levels, they emit light at characteristic wavelengths, creating a "fingerprint" for each element.

Elements with even atomic numbers are often more abundant due to the greater stability of nuclei with even numbers of protons and neutrons. This phenomenon, known as the Oddo-Harkins rule, is related to nuclear binding energies and the processes of nucleosynthesis.

Electron shielding increases with atomic number as more inner electrons shield outer electrons from the nuclear charge. This concept is crucial in understanding trends in atomic size, ionization energy, and other periodic properties.

Element 118 (Oganesson) is currently the highest atomic numbered element synthesized and the last element that fits in the traditional periodic table structure. Beyond this, new elements would require a new period and potentially new groups, challenging our current understanding of element organization.

Diagonal relationships exist between certain elements with similar properties but different atomic numbers, like lithium and magnesium. These relationships arise from a balance between atomic size and electronegativity, both influenced by atomic number.

Transition metals have similar properties due to their partially filled d-orbitals, which allow for multiple oxidation states and similar reactivity. While their atomic numbers differ, their outer electron configurations are often similar, leading to comparable chemical behaviors.

Atomic numbers determine the ground state electron configuration. In transition metals, electrons can be promoted from s to d orbitals during bonding. This promotion, possible due to the energy levels determined by atomic number, explains some of their unique properties.

Bismuth-209, with 83 protons, was long considered the heaviest stable isotope. However, it was discovered to be slightly radioactive with an extremely long half-life. This discovery challenged our understanding of nuclear stability at high atomic numbers.

Atomic numbers influence melting and boiling points through their effect on atomic size and bonding strength. Generally, these points increase across a period and decrease down a group, with exceptions due to factors like metallic bonding strength in transition metals.

Elements with consecutive atomic numbers can have very different properties if they're in different groups. For example, chlorine (17) and argon (18) have drastically different properties due to their different outer electron configurations, despite having consecutive atomic numbers.

Lanthanide contraction refers to the decrease in atomic and ionic radii across the lanthanide series (atomic numbers 57-71). This is due to poor shielding by f-electrons, leading to increased effective nuclear charge as atomic number increases.

Technetium, atomic number 43, is the lowest numbered element that does not occur naturally on Earth. All isotopes of technetium are radioactive with relatively short half-lives, illustrating how atomic structure influences nuclear stability.

In elements with high atomic numbers, electrons in inner orbitals move at speeds approaching the speed of light. These relativistic effects can influence properties like color (e.g., gold's yellow color) and chemical behavior, especially for elements with very high atomic numbers.

Elements in the same period have different properties due to their increasing number of valence electrons as atomic number increases. This leads to changes in reactivity, bonding behavior, and other chemical properties across a period.

Atomic clocks use the precise frequency of electron transitions in specific atoms, often cesium-133 (atomic number 55). The atomic number determines the electron configuration and thus the specific transition used, making it crucial for the clock's accuracy.

Plutonium, atomic number 94, is the first synthetic element to be produced in macroscopic quantities and used practically (in nuclear weapons and reactors). It represents a milestone in our ability to create and utilize synthetic elements, showcasing how understanding atomic numbers and structure can lead to technological applications.