Atoms and the Periodic Table

Questions and Answers

What are extensive properties?

Properties that depend on the amount of matter (correct)

Properties that can change the chemical composition

Properties that depend on the type of matter

Properties that are always the same

What is a homogeneous mixture?

Components can be easily distinguished

Always has a fixed ratio

Made up of more than two elements

Components are evenly distributed (correct)

What is a compound?

A substance made up of more than two elements or atoms.

Intensive properties depend on the amount of matter.

False Signup and view all the answers

Who introduced the Law of Octaves?

Newlands Signup and view all the answers

Define ionization energy.

The amount of energy required to remove an electron from an atom. Signup and view all the answers

Match the following terms with their definitions:

Atomic Radius = Distance between nucleus and valence shell Electron Affinity = Energy released when an atom gains an electron Electronegativity = Ability of an atom to attract electrons Ionization Energy = Energy required to remove an electron from an atom Signup and view all the answers

Study Notes

Matter and Properties

Matter is anything that occupies space and has mass.
Extensive properties depend on the amount of matter, e.g., mass and volume.
Intensive properties are quantity-independent and depend on the type of matter, e.g., density and color.

Mixtures

Mixtures consist of two or more substances.
Homogeneous mixtures have evenly distributed components, difficult to distinguish visually.
Heterogeneous mixtures have unevenly distributed components, easily distinguished by the eye.

Pure Substances

Pure substances can be either elements or compounds.
Elements consist of identical atoms, while compounds are made of two or more different elements in a fixed ratio.

Historical Development of the Periodic Table

Dobereiner’s Triad (1817): Similar elements grouped in threes; average atomic weight of the second equals the average of the first and third.
Newlands’ Law of Octaves (1866): Elements arranged by increasing atomic mass, with the properties of the eighth element repeating those of the first.
Mendeleev’s Table (1869): Elements’ atomic weights relate to periodic variations in properties; predicted Gallium's existence.
Henry Moseley (1894): Discovered that atomic charge (atomic number) is distinct from atomic mass.

Modern Periodic Table Structure

Metals give electrons, nonmetals accept electrons, and metalloids possess characteristics of both categories.

States of Matter

States vary from Bose-Einstein condensate (coldest) to plasma (hottest).

Properties of Matter

Physical properties do not change the substance's composition; examples include hardness and malleability.

Periodic Trends

Atomic Radius: Distance between the nucleus and valence shell; increases down the group.
Electron Affinity: Energy released when an atom gains an electron; higher affinity the closer to fluorine.
Ionization Energy: Energy required to remove an electron; increases as the atom approaches fluorine.
Electronegativity: Atom's ability to attract electrons; higher values indicate proximity to fluorine.

Description

This quiz focuses on the fundamental concepts of atoms and the periodic table, aimed at understanding matter and its properties. It covers the basic definitions, characteristics, and classifications that are crucial for mastering the subject in preparation for the midterm exam.