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Scientific notation

1. physicist measuring the quantity of electric charge in coulombs (c) found that one coulomb is equal to 6.24x10^18 electrons. about how many electrons are there in 10^3 coulombs?

2. r. millikan, a physicist, found out in his oil drop experiment that 1 electron unit (eu) is equal to 1.602x10^-19. how many coulombs are there in 10^5 eu?

3. one mole of water has a mass of 18g and contains about 6.02x10^23 molecules of water. what is the molecule content of 10^2 moles of water? what is it's mass?

4. a light year, the distance light travels in one year is about 9.44,10^12 km. if polaris is about 64 000 000 000km from earth, about how long will it take light from this star to reach earth?

(include solutions please)


  • Réponse publiée par: nila93
    1 electron in Lithium
  • Réponse publiée par: cleik
    2 Electrons ~
    { Depends on the number of protons and the charge .
    ー If the charge is zero then the number of electrons will be the same as the number of protons
    ーIf the charge is a (+) then "subtract the number of protons to the charge "
    ーBut if the charge is (-) then add the number of protons to the charge
    And will result to the number of "electrons " (^O^)/
  • Réponse publiée par: elaineeee



    The halogen elements are fluorine (F), chlorine (Cl), bromine (Br), iodine (I), astatine (At), and tennessine (Ts).

  • Réponse publiée par: kateclaire

    2, since Lithium has 3 electrons in neutral state. It loses 1 electron to form Li+ ion

  • Réponse publiée par: ian2145

    8. Dmitri Inovich Mendeleev


    Dmitrii Mendeleev (1834-1907; see portrait of Mendeleev in 1878 by Kramskoy) was born in Tobolsk, in Western Siberia. His chief contribution to chemistry was the establishment of the periodic system of elements.

  • Réponse publiée par: kirbydimaranan



    10.(see your periodic table)





  • Réponse publiée par: elishakim80


    9 electrons

    Once one shell is full, the next electron that is added has to move to the next shell. So... for the element of FLUORINE, you already know that the atomic number tells you the number of electrons. That means there are 9 electrons in a fluorine atom.

  • Réponse publiée par: hellcrack777


    9 electrons

    sana makalutlong

  • Réponse publiée par: kuanjunjunkuan


    elements in period 4 group 7a:

    flourine - 9 electrons

    chlorine - 17 electrons

    bromine - 35 electrons

    iodine - 53 electrons

    astatine - 85 electrons


    the atomic number of an element is also the number of its electrons

  • Réponse publiée par: jasminsexy

    There are 2 electrons in the Lithium ion (Li⁺)

    Further explanation

    The periodic system of elements is an arrangement of elements classified based on similar properties and their atomic number order.

    The periodic system is divided into groups (vertical order) and periods (horizontal order)

    Each element has an electron configuration.

    Determination of electron configurations based on principles:

    Hund's Rule, Aufbau's Principle, and the Pauli-exclusion principle.

    The Atomic Number (Z) indicates the number of protons in an atom of an element. If the atom is neutral then the number of protons will be equal to the number of electrons. So the atomic number can also indicate the number of electrons.

    Atoms have different stability. Unstable atomic atoms will try to form stable electron configurations like those of noble gases. Where noble gases have the number of outer electrons 2 or 8

    Lithium is located in group 1A and period 2

    Lithium has an atomic number of 3

    So it has the number of protons = the number of electrons = 3

    electron configuration Li: 1s² 2s¹ or [He] 2s¹

    To achieve stability like the noble gas element He, then Lithium will release 1 electron to form a Lithium ion which is the cation Li⁺

    So that in this Lithium ion there are 2 electrons

    Learn more  

    electron configurations using the Aufbau rule  


    the reactivity of element  


    non metals element  



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Scientific notation 1. physicist measuring the quantity of electric charge in coulombs (c) found tha...