Periodic table Test Corrections

Which of the following is true?

• An atom will be neutral if the number of protons, neutrons, and electrons are equal.

• An atom will be positive since the mass of an atom is concentrated in the positive nucleus of an atom.

• An atom will be negative since the outside of the atom is negatively charged due to the electron cloud.

Answer explanation

As long as the electrons and the protons are equal, the atom has no charge. The neutrons don't affect the charge.

Which of the following statements is true about the atom diagram above?

• The atom in the diagram is a francium atom.

• The atom in the diagram above is a nitrogen atom.

• The atom in the diagram above is a chlorine atom.

Answer explanation

This model doesn't show us what is in the nucleus of the atom. We have to count electrons instead of protons. Count 17 electrons. This means that there are 17 protons. Find element 17 on the periodic table.

Tags

NGSS.MS-PS1-1

What is true about this model?

• Since the atomic number is seven, the atom illustrated is lithium.

• The atom illustrated is an alkali metal since it has one valence electron.

• The atom illustrated has three valence electrons making it in group 13.

Answer explanation

Lithium has an atomic number of 3.

We only count valence electrons for group numbers. Valence electrons are on the OUTSIDE.

There is ONE valence electron. Therefore lithium is in group 1. Group 1 is the alkali metals.

Tags

NGSS.MS-PS1-1

What is true about the image?

• Nitrogen has an atomic mass of five.

• Nitrogen has five protons in its nucleus.

• Nitrogen has five valence electrons.

Answer explanation

This is an Electron Dot Diagram.

It shows how many valence electrons an element has.

Tags

NGSS.MS-PS1-1

Which of these is a property of alkali metals?

• they are very brittle

• they are very reactive

• they are poor conductors

Answer explanation

Metals aren't brittle- Brittle means easily broken.

Metals are great conductors. This is why we use them for pans for cooking and as wires for electricity.

Alkali metals are the most reactive metals.

Which of the following is true about Boron-10 and Boron-14?

• Both of these atoms have five protons.

• These atoms are isotopes, meaning they have the same number of neutrons.

• These atoms are the same type of atoms, meaning they have the same characteristic properties but different atomic numbers.

Answer explanation

Boron-10 and Boron-14 are ISOTOPES, but what this means is they have:

The same ATOMIC number, which is 5. They each have 5 protons.

They have different MASS numbers, meaning they have different numbers of neutrons.

Which of the following statement based on the illustration above is true about metallic elements in period four?

• Potassium (K) is the most metallic element in the illustration above since it is on the left side of the periodic table.

• Iron (Fe) is the most nonmetal element in the illustration above since it is part of the transition metals in period four.

  
  

• Krypton (Kr) is the most metallic element in the illustration above since it is on the right side of the periodic table

Answer explanation

LEFT SIDE: More Metallic.

RIGHT SIDE: Less Metallic

Find the element farthest on the left.

Tags

NGSS.HS-PS1-1

Analyzing the illustration above, which of the following statements is true?

• Calcium (Ca) is the most metallic element illustrated since it is an alkali metal.

• Arsenic (As) is the least metallic element illustrated since it is a metalloid close to the halogens.

• Vanadium (V) is the most metallic alkali metal illustrated since it is in group five.

Answer explanation

Out of the choices given, Arsenic is the least metallic. It is a metalloid on the right of the periodic table. It is closer to the halogens.

Tags

NGSS.MS-PS1-1

• The atomic number for carbon is six meaning that it has six protons in the nucleus.

• The atomic mass is twelve for carbon meaning that it has six protons and twelve neutrons in the nucleus.

• The atomic mass is eighteen for carbon meaning that it has six protons, six neutrons, and six electrons total

Tags

NGSS.MS-PS1-1

Using the periodic table reference sheet provided, which of these elements share the same properties as magnesium (Mg)?

• strontium (Sr)

• aluminum (Al)

• scandium (Sc)

Answer explanation

MG and SR are in the same GROUP, therefore they will share the most characteristics. These are the alkali earth metals.