SC 8 P 8 5

Which of these statements correctly describes the trends when moving from left to right within the period from sodium to chlorine?

• The number of valence electrons increases, and the atomic radius increases.

• The number of valence electrons increases, and the atomic radius decreases.

• The number of valence electrons decreases, and the atomic radius increases.

• The number of valence electrons decreases, and the atomic radius decreases.

The mass of an element is the sum of the atomic number and the number of __________.

• electrons

• ions

• neutrons

• protons

Tags

NGSS.MS-PS1-1

The periodic table of the elements organizes elements according to their properties. A section of the periodic table is shown.

Which set of elements below is the most similar in chemical behavior?

• H, Be, Sc

• Fr, Ra, Rf

• Ti, V, Cr

• Be, Ca, Ra

Two common liquids, water and peroxide, are both formed with atoms of hydrogen and oxygen. If both substances discussed above are made of hydrogen and oxygen, how is the make-up of the two substances different?

• The number of atoms of each element is different.

• The number of protons in the atoms of each element is different.

• The number of protons in the atoms of each element is different.

• The number of protons in the atoms of each element is different.

Tags

NGSS.MS-PS1-1

Since sodium chloride is classified as a compound, a sample of it contains...

• atoms that are gases, liquids, and solids.

• more than one kind of atom

• matter than cannot be reduced into atoms

• a solution of atoms and molecules

Tags

NGSS.MS-PS1-1

What do carbon, hydrogen, and oxygen atoms have in common?

• the same number of protons

• he same number of electrons

• neutrons located outside of the nucleus

• electrons located outside of the nucleus

Tags

NGSS.MS-PS1-1

Sodium metal (Na) reacts violently when mixed with water and produces sodium hydroxide (NaOH) and hydrogen gas (H2).

Which metal would most likely react in a similar fashion?

• magnesium (Mg)

• aluminum (Al)

• potassium (K)

• titanium (Ti)

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which of these is not an example of a pure substance?

• aluminum can

• milk

• table salt

• water

Which statement accurately compares the trends in atomic number and atomic mass in the periodic table?

• The atomic number increases from left to right, while the atomic mass increases from right to left.

• The atomic mass increases from left to right, while the atomic number increases from right to left.

• Both the atomic mass and the atomic number increase from left to right.

• Both the atomic mass and the atomic number increase from right to left.

Peter explores the periodic table and how atoms can combine to form compounds. He uses beads with different sizes and colors as models. Each different type of bead represents atoms from a different element.

How can Peter best use the beads to show how compounds form in nature?

• He can sort the beads by color and size, then join beads of the same color and size together.

• He can arrange the beads into various formations using different colors and sizes multiple times.

• He can pile all the beads together to show how all the atoms in nature join together to form one large mass.

• He can glue together a red bead and a yellow bead as well as a green bead and a blue bead to show that compounds only form from pairs of atoms.

Answer explanation

In nature, compounds do not form only from atoms of the same element; they form in combinations with many different types of elements to make unique compounds. While some molecules are large, the matter in nature is still divided into discrete molecules, not one large mass. Compounds are not always made up of pairs of atoms.

Tags

NGSS.MS-PS1-1