Chemistry

Why is magnesium atom smaller than atoms of both sodium and calcium?

The location of the outer electrons for Mg are in closer to the nucleus than of Sodium or Calcium.

To add to the correct answer from Bob Pursley, consider the electronic configurations.
11Na = 1s2, 2s2, 2p6, 3s1
12Mg = 1s2, 2s2, 2p6, 3s2
20Ca = 1s2, 2s2, 2p6, 3s2, 3p6, 4s2

The outer electron for Na "sees" a charge of +1 (11 protons in the nucleus shielded by 10 electrons from the inner shells) whereas the outer electrons for Mg "see" a +2 charge (12 protons in the nucleus shielded by 10 electrons from the inner shells). Thus the Mg electrons are drawn in further due to the increased charge.
For Ca, the outer electrons see a +2 charge, the same as Mg, (20 protons in the nucleus shielded by 18 electrons from the inner shells) BUT the outer electrons are further out(in the 4s shell instead of the 3s) and the attraction falls off because of the distance.

thanks

  1. 👍
  2. 👎
  3. 👁

Respond to this Question

First Name

Your Response

Similar Questions

  1. chemistry

    what is the mass in grams? a) 3.011 x 10^23 atoms F b)1.50 x 10^23 atoms Mg c)4.50 x 10^12 atoms Cl d)8.42 x 10^18 atoms Br e) 25 atoms w f) 1 atom Au can you please explain a and b to me then i'll come back later and see if i did

  2. Chemistry

    The experimentally measured and generally accepted value for the molar volume of Na is about 23 cm3/mol. Which of the following best explains why the value calculated in Part B is significantly smaller than the measured values?

  3. 8th grade chemistry

    2CuSO4 what does the information above represent? (A) two molecules made of one copper atom, one sulfur atom, and four oxygen atoms. (B) two elements made of one copper atom, one sulfur atom, and four oxygen atoms. (C) two copper

  4. chemistry

    When calcium chloride and ammonium phosphate are mixed, an insoluble precipitate of calcium phosphate forms and falls out of solution. After careful analysis of the purified precipitate, 8.16 * 10^25 atoms of calcium are found in

  1. Chemistry

    Calcium carbonate is insoluble in water. Name two substances that when mixed in solution, will form a precipitate of calcium carbonate. Explain why is it the two substances that you have chosen. why does magnesium chloride cannot

  2. Science--HELP!!

    Can you please check my answers: 1. Dalton's idea that atoms cannot be divided into smaller parts was disproved by the discovery of _________ (electrons?) 2. The description of the structure of the atom is called ______ (atomic

  3. chemistry

    Hard Water often contains calcium chloride. The calcium ion in solution can be detected using a solution of sodium phosphate. When a solution of calcium chloride is mixed with a solution of sodium phosphate, a precipitate forms.

  4. Science

    1. Which statement about subatomic particles is NOT true? (1 point) Protons and neutrons have almost the same mass. Protons and electrons have opposite charges. Unlike protons and electrons, neutrons have no charge. Protons and

  1. Chemistry

    A solution of 100.00mL of 0.2000mol/L sodium carbonate and 200.00mL of 0.1000mol/L calcium nitrate solutions are mixed together according to the reaction: sodium carbonate + calcium nitrate→ calcium carbonate + sodium nitrate.

  2. Chemistry

    Write the chemical formulas for the compounds containing each of the following: a) one calcium atom for every two iodide atoms. b) two nitrogen atoms for every four oxygen atoms. c) one silicon atom for every two oxygen atoms. d)

  3. Science

    18. The description of the structure of the atom is called the ___. ATOMIC MODEL 19. In a water molecule, two atoms of hydrogen and one atom of oxygen share electrons. A ______ bond is found in a water molecule. COVALENT BOND 20.

  4. Science please help

    Draw Bohr diagrams of a magnesium atom bonding with fluorine atoms. Draw atoms then electron transfer and finally the ions that form. What type of bonding occurs? Draw Bohr diagrams of 2 hyrdogen atoms bonding with an oxygen atom

You can view more similar questions or ask a new question.