Elements in the Same Family Have Similar Properties True or False

The Periodic Table

The periodic tabular array shows all the elements and their physical properties; information technology is bundled based on atomic numbers and electron configurations.

Learning Objectives

Identify the common periodic trends that can exist deduced from the periodic tabular array of elements

Key Takeaways

Key Points

• The periodic table lists all the elements, with information nearly their atomic weights, chemical symbols, and atomic numbers.
• The arrangement of the periodic tabular array leads us to visualize sure trends among the atoms.
• The vertical columns (groups) of the periodic table are arranged such that all its elements have the same number of valence electrons. All elements within a certain group thus share like properties.

Key Terms

• atomic number: The number, equal to the number of protons in an atom, that determines its chemic properties. Symbol: Z
• group: A vertical column in the periodic table, which signifies the number of valence shell electrons in an element'south cantlet.
• period: A horizontal row in the periodic tabular array, which signifies the total number of electron shells in an chemical element's atom.

Chemical element Symbols

The periodic table is structured as an 18 X 7 grid, positioned higher up a smaller double row of elements. The periodic table simply lists chemic elements, and includes each isotope of each chemical element within one cell. In the typical periodic table, each chemical element is listed by its element symbol and diminutive number. For example, "H" denotes hydrogen, "Li" denotes lithium, and and then on. Near elements are represented by the first letter or first two letters of their English language proper name, only there are some exceptions. Two notable exceptions include argent and mercury. The symbol for silver is "Ag" from Latin argentum, which means "gray" or "shining." The symbol for mercury is "Hg" from the Latinized Greek hydrargyrum, which means "water-argent." Many periodic tables include the total name of element every bit well and color-lawmaking the elements based on their phase at room temperature (solid, liquid, or gas).

The periodic table: The periodic table is a tabular brandish of all the chemical elements. The atoms are grouped in order of increasing atomic number.

Rows and Periods

The element symbol is always well-nigh accompanied by other information such as atomic number and atomic weight. Diminutive number describes the number of protons in one atom of that element. For example, an cantlet of oxygen contains eight protons. Elements are listed in order of increasing atomic number from left to right. Each row of the periodic table is called a menses and each column of the periodic tabular array is chosen a grouping (or family). Some groups have specific names like the halogens or noble gases. Elements within the aforementioned period or group have similar backdrop.

Determining Chemical Backdrop using the Periodic Table

Chemical properties of each element are adamant by the element's electronic configuration, and especially by its outermost valence electrons. An element'due south location in the periodic table is largely dependent on its electrons; the number of valence trounce electrons determines its grouping, and the type of orbital in which the valence electrons lie in determines the element'southward block. In addition, the full number of electron shells an atom determines which period it belongs to. Because of its construction, the periodic tabular array has become an extremely useful tool for assessing and predicting elemental and chemic trends.

Chemistry 3.1 Introduction to the Periodic Table – YouTube: An introduction to the periodic table which identifies metals,,nonmetals, and metalloids by location and compares and contrasts the physical properties of metals and nonmetals.

Molecules

Molecules are electrically neutral compounds made of multiple atoms bound together past chemical bonds.

Learning Objectives

Recognize the general backdrop of molecules

Key Takeaways

Key Points

• Molecules are neutral and practise non carry any charge.
• A molecule may consist of nonmetallic atoms of a single chemical element, equally with oxygen (O_two), or of different elements, equally with water (H₂O).
• The geometry and limerick of a molecule will decide its chemical and concrete backdrop.
• Isomers are molecules with the aforementioned atoms in different geometric arrangements.

Fundamental Terms

• covalent: when 2 or more nonmetallic atoms are bound together by sharing electrons.
• isomer: Molecules with the aforementioned number of atoms in different geometric arrangements.
• compound: when ii or more different atoms are held together past a covalent bond. All compounds are molecules just non all molecules are compounds.
• molecule: Two or more atoms that are held together by a chemical covalent bail.

Atoms and Molecules

An atom is defined as a basic unit of thing that contains a centralized dense nucleus surrounded by an electron cloud. When two or more atoms are held together past a chemical covalent bail, this new entity is known as a molecule. The discussion "molecule" is a loose term, and it colloquially carries unlike meanings beyond different fields of study. For example, the term "molecules" is used in the kinetic theory of gases, referring to any gaseous particle regardless of its limerick.

Most often, the term "molecules" refers to multiple atoms; a molecule may be composed of a single element, as with oxygen (O_two), or of multiple elements, such as water (H_twoO). Molecules are neutral and carry no accuse; this property distinguishes them from polyatomic ions, such as nitrate (NO₃ ^–).

caffeine molecule: Caffeine is a complicated molecule, composed of many atoms bonded to each other in a specific arrangement.

Molecular size varies depending on the number of atoms that make up the molecule. Most molecules are too small to exist seen with the naked center. The smallest molecule is diatomic hydrogen (H₂), with a bond length of 0.74 angstroms. Macromolecules are large molecules composed of smaller subunits; this term from biochemistry refers to nucleic acids, proteins, carbohydrates, and lipids. Some macromolecules may be observed by specialized microscopes.

Oft, a compound 's composition can as well be denoted by an empirical formula, which is the simplest integer ratio of its constituent chemical elements. However, this empirical formula does not e'er describe the specific molecule in question, since it provides only the ratio of its elements. The total elemental composition of a molecule tin can be precisely represented by its molecular formula, which indicates the exact number of atoms that are in the molecule.

Case

• C_viH₁₂O₆ = molecular formula for glucose
• CH₂O = empirical (simplified ratio) formula for glucose

Isomers

Isomers are molecules with the same atoms in unlike geometric arrangements. Because of these unlike arrangements, isomers ofttimes have very different chemical and concrete properties. In the film below, 1-propanol is mostly used in the synthesis of other compounds and has a less offensive scent, whereas ii-propanol is the common household booze.

propanol structural isomers: The chemical formula for propanol (C₃H_viiOH) describes several different molecules, which vary by the position of the alcohol (OH). Each molecule is a structural isomer of the other.

Ions

An ion is an atom or molecule that has a net electrical accuse because its total number of electrons is not equal to its number of protons.

Learning Objectives

Compare the different classes of ions

Central Takeaways

Key Points

• Ions are formed when the number of protons in an atom does not equal the number of electrons. If more than protons are present, the ion is positive and is known as a cation; if more than electrons are present, the ion is negative and referred to every bit an anion.
• Ions are highly reactive species. They are by and large found in a gaseous land and practise not occur in abundance on Earth. They are repelled past like electrical charges and are attracted to reverse charges.
• The electron cloud of an atom determines the size of the cantlet; added electrons (anions) increment the electron repulsion, increasing the ion's size, while cations (with less electrons) are smaller than the atom because there are fewer electrons in the cloud to repel each other.

Key Terms

• ion: An atom or group of atoms bearing an electric accuse, such as the sodium and chlorine atoms in a common salt solution.
• anion: Ions that are negatively charged because they have more electrons than protons.
• cation: Ions that are positively charged because they take more protons than electrons.

An atom is a basic unit of matter that consists of a dense nucleus composed of positively charged protons and neutral neutrons, which is surrounded by a deject of negatively charged electrons. If an atom has the same number of protons and electrons, it is electronically neutral. However, if the total number of electrons does not equal the number of protons, the cantlet has a internet electrical accuse.

Any atom or molecule with a net charge, either positive or negative, is known as an ion. An ion consisting of a single atom is a monoatomic ion; an ion consisting of 2 or more atoms is referred to as a polyatomic ion. The positive electric charge of a proton is equal in magnitude to the negative charge of an electron; therefore, the net electric charge of an ion is equal to its number of protons minus its number of electrons.

Ions are highly reactive species. They are by and large constitute in a gaseous land and practise not occur in abundance on Earth. Ions in the liquid or solid state are produced when salts interact with their solvents. They are repelled past similar electric charges and are attracted to opposite charges.

Types of Ions

There are specialized types of ions. Anions have more electrons than protons and so take a net negative charge. Cations have more protons than electrons and so have a cyberspace positive charge. Zwitterions are neutral and take both positive and negative charges at different locations throughout the molecule. Anions are generally larger than the parent molecule or cantlet, because the excess electrons repel each other and add to the concrete size of the electron cloud. Cations are generally smaller than their parent cantlet or molecule due to the smaller size of their electron clouds.

Hydrogen ions: The relationship betwixt a molecule, its cation, and its anion is shown.

An ion is denoted by writing its net negative charge in superscript immediately later the chemical construction for the atom/molecule. Conventionally the net accuse is written with the magnitude before the sign; the magnitude of singly charged molecules/atoms is by and large omitted. Monoatomic ions are sometimes also represented past Roman numerals, which designate the formal oxidation land of the element, whereas the superscripted numerals denote the net accuse. For case, Atomic number 26^two+ can exist referred to as Fe(Two). These representations tin be thought of as equivalent for monoatomic ions, but the Roman numerals cannot be applied to polyatomic ions.

Forming Ions

Ions can be formed past ionization, which is the process of a neutral atom losing or gaining electrons. Generally, the electrons are either added to or lost from the valence beat out of an atom; the inner-beat out electrons are more tightly bound to the positively charged nucleus and so do not participate in this type of chemic interaction.

Ionization generally involves a transfer of electrons between atoms or molecules. The process is motivated by the achievement of more stable electronic configurations, such as the octet rule, which states that most stable atoms and ions have eight electrons in their outermost (valence) beat out. Polyatomic and molecular ions tin can too be formed, generally by gaining or losing elemental ions, such as H⁺, in neutral molecules. Polyatomic ions are mostly very unstable and reactive.

An mutual case of an ion is Na⁺. Sodium has a +1 charge considering sodium has eleven electrons. Notwithstanding, co-ordinate to the octet rule, sodium would be more stable with x electrons (2 in its inner nigh vanquish, 8 in its outermost vanquish). Therefore, sodium tends to lose an electron to become more stable. On the other hand, chlorine tends to gain an electron to get Cl^–. Chlorine naturally has 17 electrons merely it would exist more stable with 18 electrons (ii in its inner almost shell, 8 in its second vanquish, and eight in its valence shell). Therefore, chlorine will take an electron from another atom to become negatively charged.

Periodic Properties: Part 3, Ionic Radius, Predicting Ionic Charges – YouTube: A continuation of the discussion of periodic properties, including ionic radius and how to predict ionic charges.

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Source: https://courses.lumenlearning.com/boundless-chemistry/chapter/the-periodic-table/

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