STEM Chem Midterm '25

A neutral atom may contain 8 protons,

• 9 neutrons and 10 electrons.

• 9 neutrons and 8 electrons.

• 8 neutrons and 10 electrons.

• 10 neutrons and 9 electrons.

Tags

NGSS.MS-PS1-1

The nucleus of an atom has all of the following characteristics EXCEPT that it

• is positively charged.

• contains nearly all of the atom’s mass.

• is very dense.

• contains nearly all of the atom’s volume.

The element Boron has two naturally occurring isotopes- one with an atomic mass of 10.01 and and another with an atomic mass of 11.01. Given the information provided on the periodic table, which do you think is the most abundant isotope?

• The one with an atomic mass of 10.01.

• The one with an atomic mass of 11.01.

• They are both equally as abundant.

• Not enough information is provided to answer this.

How many valence electrons does an atom of magnesium typically have?

• 2

• 3

• 12

• 24

How many valence electrons does an atom of aluminum typically have?

• 2

• 3

• 13

• 27

Which of the following would NOT be found in the nucleus of an atom?

• protons

• neutrons

• electrons

• quarks

Which statement about the arrangement of the periodic table is not true?

• Noble gases are on the right side of the periodic table.

• Metals are found on the right side of the periodic table.

• Halogens are on the right side of the periodic table.

• Transition metals are in the center of the periodic table.

What kind of charge does an ion have?

• Positive

• Negative

• Neutral

• Can be A or B

Tags

NGSS.MS-PS2-3

Which of the following elements would be the best conductor of electricity?

• Bromine

• Silicon

• Nickel

• Krypton

Tags

NGSS.HS-PS2-5

Which of the following elements would be the most reactive?

• Bromine

• Silicon

• Nickel

• Krypton