Alchemy Quiz 11

Use the table to determine the color of the flame produced by a sample of potassium bromide (KBr).

• green

• violet-green

• violet

• yellow

• violet-yellow

Answer explanation

See this resource for more information about flame tests:

https://www.compoundchem.com/2014/02/06/metal-ion-flame-test-colours-chart/

A flame test with lithium chloride, LiCl, produces a red color. A flame test with sodium sulfate, Na₂SO₄, produces a yellow-orange color. What color would you expect in a flame test with lithium sulfate, LiSO₄?

• yellow

• yellow-orange

• orange

• pink

• red

Answer explanation

See this resource for more information about flame tests:

https://www.compoundchem.com/2014/02/06/metal-ion-flame-test-colours-chart/

Lithium carbonate (Li₂CO₃) will produce a red color in fireworks or a flame. Which part of lithium carbonate is responsible for the red color?

• both parts

• carbonate (CO₃)

• lithium (Li)

• it is not possible to tell

Answer explanation

See this resource for more information about flame tests:

https://www.compoundchem.com/2014/02/06/metal-ion-flame-test-colours-chart/

If two chemical samples both produce an orange flame upon testing, which statement is most likely true?

• The samples contain different compounds.

• The samples both contain calcium atoms.

• The samples both contain chlorine atoms.

• The two samples must contain identical compounds.

Answer explanation

See this resource for more information about flame tests:

https://www.compoundchem.com/2014/02/06/metal-ion-flame-test-colours-chart/

What evidence supports the claim that chloride, Cl−, does not cause the flame to have a color?

• Lithium chloride, LiCl, and sodium chloride, NaCl, have different colors.

• Ammonium chloride, NH₄Cl, does not cause the flame to have a color.

• Sodium chloride, NaCl, and sodium nitrate, NaNO₃, both produce flames with a yellow-orange color.

• All of these statements.

Answer explanation

See this resource for more information about flame tests:

https://www.compoundchem.com/2014/02/06/metal-ion-flame-test-colours-chart/

Tags

NGSS.MS-PS1-2

Which of these compounds will give similar flame colors when heated?

1) NaCl    2) CaCl₂    3) SrCl₂    4) Sr(NO₃)₂    5) Cu(NO₃)₂

• 1, 2, and 3

• 2 and 3

• 3 and 4

• 4 and 5

Answer explanation

See this resource for more information about flame tests:

https://www.compoundchem.com/2014/02/06/metal-ion-flame-test-colours-chart/

Which is the correct shell model for the element sodium (atomic number 11)?

• A

• B

• C

• D

Answer explanation

For all elements starting with neon, the first shell contains two electrons, and the second shell contains eight. Sodium is in row 3, and has a third shell, and being in column 1 (group 1A) has only one valence electron.

Tags

NGSS.HS-PS1-1

An atom that has seven valence electrons is in which group?

• halogens

• noble gases

• alkali metals

• alkaline earth metals

Answer explanation

For all Group A elements (except for helium), the group number tells you the number of valence electrons.

Tags

NGSS.HS-PS1-1

Magnesium is an alkaline earth metal. How many valence electrons does it have?

• 1

• 2

• 3

• 4

Answer explanation

Alkaline Earth metals are in Group 2A.

Tags

NGSS.HS-PS1-1

The number of valence electrons in a calcium atom (#20) is:

• 2

• 4

• 20

• 40

Answer explanation

Calcium is in Group 2A.

Tags

NGSS.HS-PS1-1