1.)An atom of sodium contains 11 electrons, 11 protons, and 12 neutrons. What is the atomic number of sodium?

An atom has a diameter of 2.50 Å and the nucleus of that atom has a diameter of 6.00 x 10-5 Å. Determine the fraction of the volume of the atom that is taken up by the nucleus. Assume the atom and the nucleus are a sphere. fraction of atomic volume: Calculate the density of a proton, given that the mass of a proton is 1.0073 amu and the diameter of a proton is 1.69 × 10-¹5 density: m. g/cm³

Fill in the blanks. The positions of atoms on the periodic table of the ____ are determined by how many _____  are present in their nuclei; this also is called their atomic _____.  An atom's nucleus is made up of protons, which have _____ charges and ___ that do not have a ____charge.  The total of protons and neutrons in an atom defines its atomic ____ .  Two atoms with the same number of protons but different numbers of neutrons in their nuclei are considered _____ . The nucleus is surrounded by electrons, which have  charges.  Electrons are not found randomly, but occur in discrete _____ that are grouped into "shells".  The chemical properties of an atom, that is, the kinds of chemical reactions it has with other atoms or molecules, are determined by properties of its outermost set of orbitals, which is called its _____ shell.  Two atoms will react with each other if the reaction leads to a more stable state; specifically so that their valence shells are ____  .  The most common…

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Find the average atomic mass (atomic weight) for lithium on the periodic table. There are only two significant isotopes of lithium, Li-6 and Li-7. Which is the most abundant isotope ? Not a calculation.

1- For each of the following atoms, calculate the number of protons and neutrons in the nucleus and the number of electrons outside the nucleus (assume neutral atoms). element number of number of number of electrons mass number (A) symbol 126C protons (Z) neutrons 12 10 12 10 14 27 10 23,1Na 11 17 18 2- Calculate the atomic mass to four significant figures for carbon, given the following data: Isotope Exact Atomic Mass (amu) 12.00000 13.00335 Abundance in Nature (%) 98.89 1.110 12C 13C

I need help on part A and part B