Alchemy Quiz 12

What element has two electron shells and 3 valence electrons?

• Li

• Be

• B

• Mg

Answer explanation

The row number will tell you the number of electron shells. The Group A number will tell you the number of valence or outer shell electrons.

If an element is located in Group 4A of the periodic table, what can you conclude about atoms of this element?

• It has properties similar to beryllium.

• It has four valence electrons.

• It has four core electrons.

• It has four electron shells.

Answer explanation

The Group A number will tell you the number of valence electrons. Elements in the same group (column) will have similar properties.

To create an ion from a neutral atom, which of these values is changed?

• number of nuclei

• number of protons

• number of neutrons

• number of electrons

Answer explanation

Atoms can be become ions (charged atoms) by either gaining or losing outer shell electrons.

When a magnesium atom forms an ion with a noble gas configuration, what will its charge be?

• 3+

• 2+

• 1+

• 1-

• 2-

Answer explanation

Magnesium (#12 in Group 2A) has two outer shell electrons. It "wants" to be like a noble gas, with eight outer shell electrons. It's much easier for magnesium to give up two electrons than to find six more. Transferring two electrons will give magnesium the electron configuration of neon (#10) but with two more protons than neon.

Which of these are the correct labels for the two shell diagrams shown?

• a fluorine atom and a fluoride ion with a charge of 1-

• a fluorine atom and a fluoride ion with a charge of 1+

• a fluorine atom and a neon atom

• a neon ion with a charge of 1+ and a neon atom

Answer explanation

The only difference is the number of electrons. If an atom has more electrons than protons, it has a net negative charge.

Tags

NGSS.MS-PS1-1

An ion is created when what part of the atom is gained or lost?

• protons

• neutrons

• electrons

• alpha particles

Answer explanation

An ion is an atom that has different numbers of protons and electrons. Only outer shell electrons can be transferred from metals to nonmetals.

How many valence electrons do most Noble Gases have?

• 2

• 4

• 8

• 18

Answer explanation

Noble gases are in Group 8A, The group A number tells you the number of valence or outer shell electrons (with the exception of helium).

When a lithium atom forms an ion, its charge will become:

• 1+

• 1-

• 2+

• 2-

Answer explanation

Lithium is a metal in Group 1A, so has one outer shell electron. When it gives up one electron, it will have a net positive charge.

In most ionic compounds, how many electrons does each ion have in its valence shell?

• 2 or 8

• 8

• 8, 16, or 24

• a number equal to its atomic number

• a number equal to its atomic mass

Answer explanation

The total number of valence electrons for the entire compound can be a multiple of eight, but each atom that is part of that compound will have no more then eight.

The rule of zero charge states that:

• atoms gain neutrons when forming ionic compounds.

• an ionic compound contains two or more elements that have no charge.

• an atom that gains an electron must also gain a proton to remain electrically neutral.

• the charges on metal cations and nonmetal anions in an ionic compound add up to zero.

Answer explanation

This resource may be helpful:

https://www.youtube.com/watch?v=JRhi9uC2BOQ