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Chapter 4 - Atoms and Elements

4.1 - Elements and Symbols

  • Primary substances of matter are elements.

  • Chemical symbols are abbreviations of element names in a single or two-letter way.

4.2 - The Periodic Table

  • A periodic table is an atomic number that increases the arrangement of the elements.

    • The time is called a horizontal row

  • An element with similar properties is called a group in the vertical column on the periodic table.

  • Group 1a(1) is known as alkali, Group 2A(2) is referred to as alkaline earth, Group 7A(17) is known as halogens, and Group 8A(18) contains noble gasses.

    • The metals are on the left side of the heavy zigzag line on the periodic table and nonmetals are on the right-hand side of the heavy zigzag line.

    • With the exception of aluminum, metalloids are called elements along the heavy zigzag line.

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4.3 - The Atom

  • An atom is the smallest particle to preserve an element's characteristics

  • Three kinds of subatomic particles consist of atoms

    • Positive protons (+), negative charges of electrodes (-), and electrically neutral neutrons.

  • In the small, dense nucleus, the protons and neutrons are found; electrons are outside the nucleus.

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4.4 - Atomic Number and Mass Number

  • In all atoms in the same element, the atomic number indicates the number of protons.

    • The number of protons and electrons in a neutral atom is identical

  • The total number of protons and neutrons in a nucleus is the mass number.

4.5 - Isotopes and Atomic Mass

  • Isotopes are called atoms that have the same proton number, but various neutron numbers.

  • The element's atomic weight consists of the average mass of all isotopes in a natural sample.

4.6 - Electron Energy Levels

  • Each electron is energy-specific.

    • Electrons of similar energy in an atom are grouped into specific levels of energy.

  • The second level holds up to 8 electrons and the third level holds up to 18 electrons.

    • The first level is closest to the core.

  • The arrangement of electrons is written in order to place the number of electrons in this atom from the lowest energy level to the highest.

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4.7 - Trends in Periodic Properties

  • The element characteristics are linked to atom valence electrons.

    • With only a few exceptions, the same arrangement of valence electrons only differs in energy level for each group of elements

  • The electrons of Valence are represented as points around the element symbol

  • The size of an atom increases from left to right over a period, going down a group.

    • The energy needed to remove a valence electron is the energy of ionization, which decreases over time and goes from left to right.

  • The metallic nature of an element increases the number of people going down and decreases throughout a period from left to right.

https://s3.amazonaws.com/knowt-user-attachments/images%2F1638067742569-1638067742569.png

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Chapter 4 - Atoms and Elements

4.1 - Elements and Symbols

  • Primary substances of matter are elements.

  • Chemical symbols are abbreviations of element names in a single or two-letter way.

4.2 - The Periodic Table

  • A periodic table is an atomic number that increases the arrangement of the elements.

    • The time is called a horizontal row

  • An element with similar properties is called a group in the vertical column on the periodic table.

  • Group 1a(1) is known as alkali, Group 2A(2) is referred to as alkaline earth, Group 7A(17) is known as halogens, and Group 8A(18) contains noble gasses.

    • The metals are on the left side of the heavy zigzag line on the periodic table and nonmetals are on the right-hand side of the heavy zigzag line.

    • With the exception of aluminum, metalloids are called elements along the heavy zigzag line.

https://s3.amazonaws.com/knowt-user-attachments/images%2F1638067742487-1638067742487.png

4.3 - The Atom

  • An atom is the smallest particle to preserve an element's characteristics

  • Three kinds of subatomic particles consist of atoms

    • Positive protons (+), negative charges of electrodes (-), and electrically neutral neutrons.

  • In the small, dense nucleus, the protons and neutrons are found; electrons are outside the nucleus.

https://s3.amazonaws.com/knowt-user-attachments/images%2F1638067742734-1638067742734.png

4.4 - Atomic Number and Mass Number

  • In all atoms in the same element, the atomic number indicates the number of protons.

    • The number of protons and electrons in a neutral atom is identical

  • The total number of protons and neutrons in a nucleus is the mass number.

4.5 - Isotopes and Atomic Mass

  • Isotopes are called atoms that have the same proton number, but various neutron numbers.

  • The element's atomic weight consists of the average mass of all isotopes in a natural sample.

4.6 - Electron Energy Levels

  • Each electron is energy-specific.

    • Electrons of similar energy in an atom are grouped into specific levels of energy.

  • The second level holds up to 8 electrons and the third level holds up to 18 electrons.

    • The first level is closest to the core.

  • The arrangement of electrons is written in order to place the number of electrons in this atom from the lowest energy level to the highest.

https://s3.amazonaws.com/knowt-user-attachments/images%2F1638067742276-1638067742276.png

4.7 - Trends in Periodic Properties

  • The element characteristics are linked to atom valence electrons.

    • With only a few exceptions, the same arrangement of valence electrons only differs in energy level for each group of elements

  • The electrons of Valence are represented as points around the element symbol

  • The size of an atom increases from left to right over a period, going down a group.

    • The energy needed to remove a valence electron is the energy of ionization, which decreases over time and goes from left to right.

  • The metallic nature of an element increases the number of people going down and decreases throughout a period from left to right.

https://s3.amazonaws.com/knowt-user-attachments/images%2F1638067742569-1638067742569.png