description An element in Period 1 and Group 34. A nonmetal in Group 6A A noble gas with a higher atomic number than sodium. A transition element in Period 2. Does any element with 2 s 92 match the description? O Yes O Yes O Yes O Yes O No O O No No No If you checked yes, give the symbol of an element with Zs 92 that matches. 0 0 0 0

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.

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)?

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.

What is the name of the element in Group 4A and Period 5?

Identify each of the following elements: a. a member of the same family as oxygen whose most stable ion contains 54 electrons b. a member of the alkali metal family whose most stable ion contains 36 electrons c. a noble gas with 18 protons in the nucleus d. a halogen with 85 protons and 85 electrons

2.87 What is the heaviest element to have an atomic weight that is roughly twice its atomic number? What does this suggest must he true about the nuclei of atoms with higher atomic numbers?

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)

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.

The element gallium, used in gallium arsenide semiconductors, has an atomic weight of 69.72 amu. There are only two isotopes of gallium, Ga with a mass of 6.9257 amu and Ga with a mass of 70.9249 amu. What are the isotopic abundances of gallium? Gallium melts just above room temperature