Exam 2: Atoms, Elements, and Compounds

When a particular solid sample is examined under a microscope, it is observed that there are regions that are black and regions which are yellow. What type of matter is this sample?

Write the chemical symbol for the elements that is in period 2 and group 8A of the periodic table.

The electron arrangement for Na would be: shell 1: 2 electrons shell 2: 8 electrons shell 3: 1 electron

Based on the text periodic table and using the correct number of significant figures, enter the appropriate number in the blank. The mass of 7.00 mol of sodium chloride, NaCl, is _____________g.

The atomic weight of phosphorus (P) is 30.91 amu or about 31 amu. This indicates that each P atom consists of 15 protons and 16 neutrons.

Sodium is a highly reactive metal and chlorine is a toxic gas, but when they come together the resulting material, sodium chloride (a white solid), is essential for life. Which of the following is true when sodium and chlorine are brought into contact with one another?

Enter the chemical symbol of the element in the blank. An element in period 3 has the Lewis structure: X should be replaced with what chemical symbol? Chemical symbol:_____________________.

A person drinks 1900 g of water, H₂O, per day. How many moles of water did they consume?

Consider the atomic view of a substance shown below. This substance would be classified as a(n)

Enter the chemical symbol of the element in the blank. An element has the following electron arrangement. shell 1: 2 electrons shell 2: 8 electrons shell 3: 18 electrons shell 4: 18 electrons shell 5: 4 electrons The reactivity of this element would most closely resemble that of which element? Chemical symbol:_____________________

Indicate the number of dots that should be placed around the Lewis symbol for the following element. Use an integer: 1, 2, 3, etc. as appropriate. Br

Neutral isotopes of the same element have the same number of electrons.

What is the meaning of the subscripts in the formula for ethyl alcohol, C₂H₅OH?

Naturally occurring lithium (Li) consists of only two isotopes, Li-6 (6.02 amu) and Li-7 (7.02 amu), where the exact isotopic masses are given in parentheses. Use the periodic table and determine which isotope is present in the larger percentage in the natural element.

In 22.99 g of Na there is 6.022 × 10²³ atoms of Na.

Electron shells define a region in space around the nucleus occupied by certain electrons.

An elements with an electron arrangement of: shell 1: 2 electrons shell 2: 8 electrons shell 3: 18 electrons shell 4: 18 electrons shell 5: 7 electrons would have 1 valence electron.

Use the periodic table to determine about how many helium atoms (He) on the average would be needed to get close to the same mass as an oxygen atom (O).

Based on the text periodic table and using the correct number of significant figures, enter the appropriate number in the blank. There are _______mol is 54.05 g of boron.

Sodium chlorate, an ingredient in many common herbicides, has sodium, chlorine and oxygen atoms in the ratio 1:1:3, respectively. What is the formula unit for sodium chlorate?