{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

CH1010 Lecture 2

Themodernatomicmassstandardisthe carbon12atom

Info icon This preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: symbolized He has 2 electrons and two protons Carbon­ symbolized C has 6 electrons, 6 protons and 6 neutrons How the elements differ How the elements differ We arrange the elements in a table called The Periodic Table This Table Identifies each element by the number of protons and the mass From the number of protons and mass we can determine the number of neutrons More on Mass Later!! The modern periodic table. The Differences within Elements Differences Isotopes­ atoms of the same element with different Mass Why??­ due to different number of neutrons E.g. Carbon 12 ­ 12C vs. Carbon 14 ­ 14C The Periodic Table gives the mass as the average of all isotopes present E.G. Carbon is listed as 12.01 Isotopes Isotopes Mass number 12 C 13 C 14 C Atomic Symbols, Isotopes, Numbers A Z X The Symbol of the Atom or Isotope X = Atomic symbol of the element A = mass number; A = Z + N Z = atomic number (the number of protons in the nucleus) N = number of neutrons in the nucleus Isotope = atoms of an element with the same number of protons, but a different number of neutrons Ions – Charged Species Ions – Charged Species Atoms can gain or lose one or more electrons to produce charged species 23 Na 11 Loss of an electr on 23 Na 11 + + 1 el ectr on 35 Cl 17 + 1 el ectr on G ain of an electr on 35 Cl 17 - Atomic Masses Atomic Masses All isotopes have nearly identical chemical behavior The Mass of an atom is measured relative to the mass of an atomic standard The modern atomic mass standard is the carbon 12 atom C12 is defined as exactly 12 atomic mass units or amu’s Atomic Masses Atomic Masses Based on C12 defined as exactly 12 amu’s 1H has a mass of 1.008 amu’s The unit dalton (Da)...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern