Which of the following gives the correct numbers of protons, neutrons, and electrons, respectively, in a neutral atom of  Sn?

EXTRA CREDIT The following electron configurations contain a coded word. [Xe] 6s² 1s²2s²2p63s1 [Ne] 3s1 1s²2s²2p63s23p4 The coded word is (use all lowercase letters)

How many grams of MgO are produced when 40.0 grams of O2 react completely with Mg in the following reaction 2 Mg (s) + O2 (g) –> 2 MgO (s)

An element has two naturally occurring isotopes. One isotope has a mass = 35.0 amu and makes up 24.2% of the sample, the other isotope has a mass = 37.0 amu and makes up 75.8% of the sample. What is the average atomic mass for this element?

What is the symbol of the element in Group 4A (14) in Period 2?

The Group 8A (18) elements are called the

The number of electrons in the outer energy level (ie., number of valence electrons) of a neutral atom of boron (atomic number 5) is:

The correct conversion factor to calculate the number of Liters in 5,687 ml is:

A package of hardware parts has 180 washers, 93 bolts, 44 nuts, and 19 spacers.  What percentage of the parts are spacers? 

Solve this equation:  18 + (8 x 4) x 53 – (8 – 4) + 44 =