Periodic Table and periodicity

Criteria for a new element discovery

Assessing if an element has been “discovered” is not a simple task. While reviewing the discovery profiles of the transfermium Elements in the early 90s’, IUPAC and IUPAP set up to establish a series of criteria that must be satisfied for the discovery of an element to be recognized.

Temporary name and symbol

While an element can have been claimed, before the claim has been validated and before the element is formally named, the element has a temporary name and symbol.

Validation and assignation of an element discovery

Claims for the discoveries of new elements appear time to time in the scientific literature. IUPAC, along with IUPAP, is involved in assessing these claims. In result, IUPAC technical reports are released that review each pertaining references and recognize the laboratory whose claims fulfill the agreed criteria.

Naming new element

When the discovery of a new element has been validated and the priority for its discovery has been assigned, the naming process can begin. The Laboratory to which the discovery has been assigned is invited to propose a name and symbol. IUPAC will then review the proposal, and if agreed, after an additional 5-month public review, will formalize the name.

Periodicity

Periodicity refers to trends or recurring variations in element properties with increasing atomic number. Periodicity is caused by regular and predictable variations in element Atomic structure.

Mendeleev organized elements according to recurring properties to make a periodic table of elements. Elements within a group (column) display similar characteristics. The rows in the periodic table (the periods) reflect the filling of electrons shells around the nucleus, so when a new row begins, the elements stack on top of each other with similar properties. For example, helium and neon are both fairly unreactive gases that glow when an electric current is passed through them. Lithium and sodium both have a +1 oxidation state and are reactive, shiny metals.

Periodicity was helpful to Mendeleev because it showed him gaps in his periodic table where elements should be. This helped scientists find new elements because they could be expected to display certain characteristics based on the location they would take in the periodic table. Now that the elements have been discovered, scientists and students used periodicity to make predictions about how elements will behave in chemical reactions and their physical properties. Periodicity helps chemists predict how the new, superheavy elements might look and behave.

Periodicity can include many different properties, but the key recurring trends are:

Ionization Energy

This is the energy needed to completely remove an electron from an atom or ion. Ionization energy increases moving left to right across the table and decreases moving down a group.

Electronegativity

A measure of how readily an atom forms a chemical bond. Electronegativity increases moving left to right across a period and decrease moving down a group.

Atomic Radius

This is half the distance between the middle of two atoms just touching each other. Atomic radius decreases moving left to right across a period and increases moving down a group. Ionic radius is the distance for ions of the atoms and follows the same trend.

Electron Affinity

This is a measure of readily an atom accepts an electron. Electron affinity increases moving across a period and decreases moving down a group. Nonmetals usually have higher electron affinities than metals.,

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Sure, here are some frequently asked questions and short answers about the topics of elements, compounds, and mixtures:

What is an element?

An element is a substance that cannot be broken down into any other substances by chemical means. The elements are the basic building blocks of matter, and there are 118 known elements.

What is a compound?

A compound is a substance that is made up of two or more elements that are chemically combined. Compounds can be represented by chemical formulas, which show the elements that are present in the compound and the ratio of the atoms of each element.

What is a mixture?

A mixture is a substance that is made up of two or more substances that are not chemically combined. Mixtures can be classified into two types: homogeneous mixtures and heterogeneous mixtures. Homogeneous mixtures are mixtures that have the same composition throughout. Heterogeneous mixtures are mixtures that have different compositions in different parts of the mixture.

What are the different types of elements?

The elements can be classified into metals, nonmetals, and metalloids. Metals are elements that are shiny, good Conductors of heat and electricity, and ductile (can be drawn into wires). Nonmetals are elements that are dull, poor conductors of heat and electricity, and brittle. Metalloids are elements that have properties of both metals and nonmetals.

What are the different types of compounds?

The compounds can be classified into ionic compounds, covalent compounds, and molecular compounds. Ionic compounds are compounds that are formed when ions (charged particles) are attracted to each other. Covalent compounds are compounds that are formed when atoms share electrons. Molecular compounds are compounds that are formed when atoms share electrons and the electrons are not shared equally.

What are the different types of mixtures?

The mixtures can be classified into homogeneous mixtures and heterogeneous mixtures. Homogeneous mixtures are mixtures that have the same composition throughout. Heterogeneous mixtures are mixtures that have different compositions in different parts of the mixture.

What are the properties of elements?

The properties of elements can be classified into physical properties and chemical properties. Physical properties are properties that can be observed without changing the composition of the element. Chemical properties are properties that can only be observed when the element reacts with another substance.

What are the properties of compounds?

The properties of compounds can be classified into physical properties and chemical properties. Physical properties are properties that can be observed without changing the composition of the compound. Chemical properties are properties that can only be observed when the compound reacts with another substance.

What are the properties of mixtures?

The properties of mixtures can be classified into physical properties and chemical properties. Physical properties are properties that can be observed without changing the composition of the mixture. Chemical properties are properties that can only be observed when the mixture reacts with another substance.

What are the uses of elements?

The elements are used in a variety of products and applications. Some of the most common uses of elements include:

Metals are used in construction, transportation, and manufacturing.
Nonmetals are used in batteries, electronics, and insulation.
Metalloids are used in semiconductors, solar cells, and lasers.
What are the uses of compounds?

The compounds are used in a variety of products and applications. Some of the most common uses of compounds include:

Ionic compounds are used in batteries, Fertilizers, and detergents.
Covalent compounds are used in plastics, rubber, and solvents.
Molecular compounds are used in food, water, and air.
What are the uses of mixtures?

The mixtures are used in a variety of products and applications. Some of the most common uses of mixtures include:

Homogeneous mixtures are used in gasoline, paint, and cosmetics.
Heterogeneous mixtures are used in concrete, Soil, and blood.

Sure, here are some MCQs without mentioning the topic Periodic Table and Periodicity:

Which of the following is not a property of metals?
(A) They are good conductors of heat and electricity.
(B) They are shiny.
(C) They are malleable.
(D) They are ductile.
Which of the following is not a property of non-metals?
(A) They are poor conductors of heat and electricity.
(B) They are dull.
(C) They are brittle.
(D) They are non-lustrous.
Which of the following is not a property of metalloids?
(A) They have properties of both Metals and Non-metals.
(B) They are semiconductors.
(C) They are brittle.
(D) They are non-lustrous.
Which of the following is the most electronegative element?
(A) Fluorine
(B) Oxygen
(C) Chlorine
(D) Bromine
Which of the following is the most electropositive element?
(A) Francium
(B) Cesium
(C) Potassium
(D) Sodium
Which of the following is the most reactive element?
(A) Fluorine
(B) Oxygen
(C) Chlorine
(D) Bromine
Which of the following is the least reactive element?
(A) Francium
(B) Cesium
(C) Potassium
(D) Sodium
Which of the following is the most abundant element in the Earth’s crust?
(A) Oxygen
(B) Silicon
(C) Aluminum
(D) Iron
Which of the following is the most abundant element in the universe?
(A) Hydrogen
(B) Helium
(C) Oxygen
(D) Carbon
Which of the following is the most common gas in the Earth’s Atmosphere?
(A) Nitrogen
(B) Oxygen
(C) Argon
(D) Carbon dioxide
Which of the following is the most common liquid on Earth?
(A) Water
(B) Oil
(C) Seawater
(D) Mercury
Which of the following is the most common solid on Earth?
(A) Rock
(B) Soil
(C) Sand
(D) Ice
Which of the following is the most common Metal on Earth?
(A) Iron
(B) Aluminum
(C) Copper
(D) Gold
Which of the following is the most common non-metal on Earth?
(A) Oxygen
(B) Silicon
(C) Aluminum
(D) Carbon
Which of the following is the most common metalloid on Earth?
(A) Arsenic
(B) Germanium
(C) Silicon
(D) Boron

I hope these MCQs are helpful!