Periodic Table Overview and History

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Questions and Answers

What is the primary reason atoms react in accordance with the octet rule?

To achieve high energy levels

To obtain a full set of eight valence electrons (correct)

To create more stable isotopes

To maintain a balanced charge

Which of the following best describes a polyatomic ion?

A neutral atom with an even number of protons and electrons

An ion consisting of two or more atoms with a charge (correct)

An ion formed from the loss of a single electron

An ion that can only act as a cation

How do Lewis symbols visually represent valence electrons?

With colored circles around the element's symbol

By placing dots around the element's symbol (correct)

Using horizontal lines between each pair of electrons

Through shading the element's symbol

What type of ion is formed when an atom loses electrons?

Cation Signup and view all the answers

What does the octet rule indicate about nitrogen's valence electrons?

Nitrogen needs 3 more electrons to complete its octet Signup and view all the answers

What is electronegativity?

The tendency of an atom to attract electrons Signup and view all the answers

What is the trend for metallic property as you move top to bottom in the periodic table?

it increases Signup and view all the answers

What trend does ionization energy follow as you move from top to bottom in a group of the periodic table?

Decreases Signup and view all the answers

Which of the following is NOT a property characteristic of metals?

Brittleness Signup and view all the answers

Which of the following is a monomer of carbohydrates?

Glucose Signup and view all the answers

What is the primary energy source among biomolecules?

Carbohydrates Signup and view all the answers

What defines non-metals in terms of their ability to form ions?

They easily gain electrons to form anions. Signup and view all the answers

What happens to electron affinity as you move from left to right across a period?

Increases Signup and view all the answers

As you move from left to right across a period, how does metallic property change?

It decreases. Signup and view all the answers

Which of the following statements about disaccharides is correct?

They are composed of two monosaccharides bonded together. Signup and view all the answers

What is the electronegativity range for metalloids?

1.8 to 2.1 Signup and view all the answers

What is the trend in electronegativity as you move from top to bottom in the periodic table?

Decreases Signup and view all the answers

What is the effect of atomic size as one moves down a group in the periodic table?

Atomic size increases. Signup and view all the answers

What is a common property of non-metals that distinguishes them from metals?

They have a dull appearance. Signup and view all the answers

What best describes a polymer?

A complex molecule made of many monomers Signup and view all the answers

Which of the following correctly states the trend for non-metallic property across a period?

It increases from left to right. Signup and view all the answers

What are the basic building blocks of lipids?

Glycerol and fatty acids Signup and view all the answers

Which of the following is NOT a polysaccharide?

Maltose Signup and view all the answers

What is the primary function of nucleic acids in living organisms?

Transmitting genetic information Signup and view all the answers

Which elements are present in proteins?

Carbon, hydrogen, oxygen, and nitrogen Signup and view all the answers

What type of molecule is formed when glycerol binds with three fatty acids?

Triglyceride Signup and view all the answers

Which statement is true regarding valence electrons?

They are responsible for chemical bonding Signup and view all the answers

What are amino acids classified as in the context of proteins?

Monomers Signup and view all the answers

Which of the following best describes the octet rule?

Atoms combine to achieve a more stable electron configuration Signup and view all the answers

Which scientist is known for organizing the elements by increasing atomic number using x-rays?

Henry Moseley Signup and view all the answers

What is the significance of Mendeleev's arrangement of elements?

He left gaps for undiscovered elements while grouping by similar properties. Signup and view all the answers

What does the term 'periodicity' refer to in the context of the periodic table?

The repeating patterns in chemical and physical properties. Signup and view all the answers

What did John Newlands contribute to the periodic table?

He introduced the Law of Octaves using atomic mass. Signup and view all the answers

In the modern periodic table, what distinguishes groups from periods?

Groups are vertical columns, while periods are horizontal rows. Signup and view all the answers

What was one of John Dalton’s main contributions to the early concept of the periodic table?

He established atomic weights for the first elements discovered. Signup and view all the answers

Which of the following statements about non-metals in the periodic table is true?

Non-metals are predominantly found on the right side of the table. Signup and view all the answers

What was the primary basis of Johann Dobereiner's classification of elements?

He grouped them in sets of three based on atomic weights. Signup and view all the answers

Study Notes

Periodic Table

A useful tool for organizing elements
Arranged by increasing atomic number, left to right
Columns are called groups, elements in the same groups share similar properties
Rows are called periods
IUPAC (International Union of Pure and Applied Chemistry) updates and monitors the table
Metals are generally on the left and center; nonmetals are on the right
Elements are arranged into vertical columns called groups or families and horizontal rows called periods or series

History of the Periodic Table

1808: John Dalton theorized that atoms of the same element are the same
1817: Johann Dobereiner proposed the Law of Triads, grouping elements into sets of three based on atomic weights
1864: John Newlands proposed the Law of Octaves, noticing repeating patterns every eighth element when ordered by increasing atomic mass
1869: Dimitri Mendeleev, considered the "Father of the Modern Periodic Table", arranged elements by increasing atomic mass and grouped them by similar chemical and physical properties
1913: Henry Moseley rearranged elements by increasing atomic number, improving the accuracy of the periodic table

Periodic Trends

Systematic variations in element properties across the table
Metallic properties: The ability of an atom to lose an electron. Increases from top to bottom, decreases left to right
Non-metallic properties: The ability of an atom to gain electrons. Increases from left to right, decreases top to bottom
Atomic size: Half the distance from the nucleus to the outermost shell. Decreases left to right, increases top to bottom
Ionization energy: Energy required to remove the most loosely bound electron. Increases left to right, decreases top to bottom
Electron affinity: Energy released when an atom gains an electron. Increases left to right, decreases top to bottom
Electronegativity: Tendency of an atom to attract electrons when bonding. Increases left to right, decreases top to bottom

Biomolecules

Important for the survival of living cells
Include lipids, nucleic acids, carbohydrates, and proteins
Monomers: Small, basic molecules that bond to form larger, more complex molecules called polymers
Carbohydrates: Organic compounds made of carbon, hydrogen, and oxygen; primary energy source (sugars, starches, fibers)
Lipids: Fatty compounds; essential for energy storage, structure, protection, signaling (glycerol, fatty acids)
Proteins: Large, complex molecules made up of amino acids
Nucleic acids: Store and transmit genetic information (nucleotides)

Chemical Bonding and Lewis Structures

Chemical bonds: Forces holding atoms together in compounds
Valence electrons: Electrons in the outermost shell of an atom, play an important role in bond formation
Lewis Structures: Diagrams showing the arrangement of valence electrons in molecules
Octet rule: Atoms tend to react in order to gain, lose, or share electrons to achieve a full outermost electron shell (8 valence electrons)

Types of Ions

Monatomic ions: Single atoms with a positive or negative charge formed by losing or gaining electrons
Polyatomic ions: Groups of two or more atoms that carry an overall charge due to the gain or loss of electrons

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Description

Dive into the essential features of the periodic table, a crucial tool for understanding elements and their relationships. Learn about its layout, including groups and periods, as well as the historical milestones that led to its current form, with insights from key scientists like Mendeleev and Dalton.