Organization of the Periodic Tabore Read each description in the first column of the table below. If any chemical element with atomic number of 92 or less matches the description, check Yes and enter the chemical symbol of an element that matches. Otherwise check No in the second column. description If you checked yes, give the symbol of an element with 2592 that matches. Does any element with 2 5 92 match the description? An element in Period 6 and Group 6A. O Yes No A nonmetal in Group A No An element in the nitrogen family with a higher atomic number than senon Yes No A transition element in Period 3. No D 0 D f x do

Mass spectrometric analysis showed that there are four isotopes of an unknown element having the following masses and abundances: Three elements in the periodic table that have atomic weights near these values are lanthanum (La), atomic number 57, atomic weight 138.9055; cerium (Ce), atomic number 58, atomic weight 140.115; and praseodymium (Pr), atomic number 59, atomic weight 140.9076. Using the data above, calculate the atomic weight, and identify the element if possible.

The symbols for most elements are based on the first few letters of the respective element’s common English name. In some cases, however, the symbol seems to have nothing to do with the element’s common name. Give three examples of elements whose symbols are not directly derived from the element’s common English name.

Given that the periodic table is an organizational scheme for the elements, what might be some other logical ways in which to group the elements that would provide meaningful chemical information in a periodic table of your own devising?

An element has the following natural abundances and isotopic masses: 90.92% abundance with 19.99 amu, 0.26% abundance with 20.99 amu, and 8.82% abundance with 21.99 amu. Calculate the average atomic mass of this element.

Which of the following is{are) correct? a. 40Ca2 contains 20 protons and 18 electrons. b. Rutherford created the cathode-ray tube and was the founder of the charge-to-mass ratio of an electron. c. An electron is heavier than a proton. d. The nucleus contains protons, neutrons, and electrons.

Calculate the atomic mass of each of the following elements using the given data for the percentage abundance and mass of each isotope. a. Lithium: 7.42% 6Li (6.01 amu) and 92.58% 7Li (7.02 amu) b. Magnesium: 78.99% 24Mg (23.99 amu), 10.00% 25Mg (24.99 amu), and 11.01% 26Mg (25.98 amu)

Here are three fictitious elements and a molecular view of the atoms that compose them. The molar mass of the middle element, (b), is 25 grams per dozen (g/doz). (The atoms of these fictitious elements are much larger than ordinary atoms.) Based on the size of the atoms, do you expect the atomic masses of elements (a) and (c) to be greater than or less than (b)? How many atoms are present in 175 g of element (b)?

a. Classify the following elements as metals or nonmetals: Mg Si Rn Ti Ge Rn Au B Am Bi At Br b. The distinction between metals and nonmetals is really not a clear one. Some elements, called metalloids, are intermediate in their properties. Which of these elements would you reclassify as metalloids? What other elements in the periodic table would you expect to be metalloids?

Determine whether the statements given below are true or false. (a) The mass of an atom can have the unit mole. (b) In N204, the mass of the oxygen is twice that of the nitrogen. (c) One mole of chlorine atoms has a mass of 35.45 g. (d) Boron has an average atomic mass of 10.81 amu. It has two isotopes, B-10 (10.01 amu) and B-11 (11.01 amu). There is more naturally occurring B-10 than B-11. (e) The compound C6H12O2N has for its simplest formula C3H6ON1/2. (f) A 558.5-g sample of iron contains ten times as many atoms as 0.5200 g of chromium. (g) If 1.00 mol of ammonia is mixed with 1.00 mol of oxygen the following reaction occurs, 4NH3(g)+5O2(g)4NO(g)+6H2O(l)All the oxygen is consumed. (h) When balancing an equation, the total number of moles of reactant molecules must equal the total number of moles of product molecules.