Chemistry & Physics 8th STAAR Review

Which statement correctly describes the location and charge of the electrons in an atom?

• The electrons are inside the nucleus and have no charge.

• The electrons are outside the nucleus and have no charge.

• The electrons are inside the nucleus and have a negative charge.

• The electrons are outside the nucleus and have a negative charge.

What is the TOTAL number of protons, neutrons, and electrons in a potassium, K, atom that has a mass of 40?

• 58

• 40

• 59

• 19

How many protons, neutrons, and electrons are present in an atom of hafnium, Hf, with a mass number of 178?

• 72 protons, 178 neutrons, 106 electrons

• 178 protons, 250 neutrons, 72 electrons

• 106 protons, 72 neutrons, 106 electrons

• 72 protons, 106 neutrons, 72 electrons

Based on the information in the table, which conclusion about the chemical reactivity of these elements is valid?

(Chemical reactivity depends on the valence electrons)

• Boron is the most reactive because it has the most protons.

• Flourine is the most reactive because it has 7 electrons in the outer shell.

• Silicon is the most reactive because it has an equal number of protons and neutrons.

• Gallium is the most reactive because it has many more neutrons than protons.

Based on the information shown in the table, which student's responses are correct?

• Student 1

• Student 2

• Student 3

• Student 4

Students were asked to identify the location of elements in the periodic table based on clues. Based on the data, which periodic table shows the correct location of the four elements?

• 
• 
• 
• 

Which properties describes the elements in Group 18?

• They are chemically stable and liquid at room temperature.

• They have eight valence electrons and are flammable.

• They are magnetic and boil at low temperatures.

• They are gaseous at room temperature and chemically stable.

Which two elements on the periodic table are in the same period?

(At the end of a sentence you place a PERIOD)

• Sn (50) and Rb (37)

• F (9) and Cl (17)

• K (19) and Ba (56)

• Se (34) and Te (52)

A student is studying the ways different elements are similar to one another. Which two atoms are of elements with similar chemical properties/reactivity on the periodic table?

(Identify each atom before picking your answer)

• Atoms 1 and 2

• Atoms 1 and 4

• Atoms 2 and 3

• Atoms 3 and 4

Students made ball-and-stick models of the substances being studied. The key shows the elements students used in their models. Which model represents an organic compound?

(C H O P S N)

• 
• 
• 
•