Chemical and Physical Changes

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Questions and Answers

What is the primary difference in chemical behavior between metals and non-metals during chemical reactions?

Metals tend to lose electrons, while non-metals tend to gain electrons.

What is the unique property of metalloids that allows them to exhibit both metallic and non-metallic characteristics?

They can exhibit properties of both metals and non-metals depending on the conditions.

What is the defining characteristic of a pure substance, and how does it relate to the concept of an element or compound?

A pure substance is a substance that consists of only one element or compound, and nothing else.

What is the process by which a metal loses electrons to form a cation, and how does this process contribute to the formation of an ionic compound?

The metal gives its lone valence electrons to the non-metal, resulting in the formation of a cation and an anion, which are held together by an ionic bond. Signup and view all the answers

What is the role of the non-metal in the formation of an ionic compound, and how does its electronegativity influence the bonding process?

The non-metal receives the electrons from the metal, resulting in the formation of an anion, and its stronger electronegativity allows it to attract the electrons. Signup and view all the answers

What is the name of the bond that holds together an ionic compound, and how does it arise from the transfer of electrons between a metal and a non-metal?

The bond is called an ionic bond, and it arises from the electrostatic attraction between the positively charged cation and the negatively charged anion. Signup and view all the answers

What is the fundamental difference between a physical change and a chemical change?

A physical change is a change in a substance's physical features, whereas a chemical change is a transformation from one substance to another, involving the rearrangement of atoms to form new products with different characteristics. Signup and view all the answers

What is the significance of the atomic number in the periodic table?

The atomic number in the periodic table can be used to determine the number of electrons and protons in an atom, and also to find the number of neutrons by subtracting the atomic mass from the atomic number. Signup and view all the answers

What is the characteristic that defines the noble gases in group 18?

The noble gases in group 18 have a stable number of 8 valence electrons, which makes them unreactive. Signup and view all the answers

What is the main difference between the qualitative properties of metals and non-metals?

Metals are conductive, ductile, and shiny, whereas non-metals are non-conductive, dull, and non-ductile. Signup and view all the answers

What is the characteristic that distinguishes the alkali metals from the alkaline earth metals?

The alkali metals are the most reactive metals and are located in group 1, whereas the alkaline earth metals are the second most reactive metals and are located in group 2. Signup and view all the answers

What is the role of subatomic particles in forming atoms and compounds?

Subatomic particles, including protons, electrons, and neutrons, make up atoms and come together to form compounds and other substances. Signup and view all the answers

What is the characteristic that defines the halogens in group 17?

The halogens in group 17 are the most reactive non-metals. Signup and view all the answers

What is the significance of the transition metals in group 3-12?

The transition metals in group 3-12 are metals with a varying amount of reactivity. Signup and view all the answers

Study Notes

Physical and Chemical Changes

A physical change is a change in a substance's physical features, whereas a chemical change involves the transformation of one substance to another.
In a chemical change, atoms in the reactants rearrange themselves and bond together differently to form new products with unique characteristics.

Atomic Structure

Atoms are the smallest unit of matter, consisting of subatomic particles: protons (positive), electrons (negative), and neutrons.
Protons and neutrons reside in the nucleus, while electrons orbit around it.
The atomic number in the periodic table indicates the number of electrons and protons in an atom.

Periodic Table and Reactivity

Alkali metals (Group 1, except hydrogen) are the most reactive metals.
Alkaline earth metals (Group 2) are the second most reactive metals.
Transition metals (Groups 3-12) have varying reactivity.
Halogens (Group 17) are the most reactive nonmetals.
Noble gases (Group 18) have no reactivity due to their stable 8 valence electrons.

Properties of Metals, Nonmetals, and Metalloids

Qualitative Properties

Metals: Conductive, ductile, shiny
Nonmetals: Non-conductive, dull, non-ductile
Metalloids: Brittle, solid at room temperature

Quantitative Properties

Metals: High melting points, high density, atomic mass
Nonmetals: Low melting points, low density, atomic mass

Chemical Properties

Metals: Tend to lose electrons during chemical bonding, prone to corrosion or oxidation
Nonmetals: Tend to gain electrons during chemical reactions
Metalloids: Can exhibit properties of both metals and nonmetals, depending on conditions; reactivity varies, can form both cations and anions

Pure Substances and Ionic Compounds

A pure substance consists of the same element or compound with no impurities.
Ionic compounds form through ionic bonding between two or more elements (one metal, one nonmetal).
Cations (metal ions) are positively charged, whereas anions (nonmetal ions) are negatively charged.

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Description

Distinguish between physical and chemical changes, understanding the formation of new substances and the role of atoms and subatomic particles.