Element's Identity and Valence Electrons

An atom would become a different element if which characteristic changed?

• The number of protons

• The number of neutrons

• The number of energy levels

• The number of valence electrons

Sodium and Lithium have similar chemical properties. What characteristic of these elements explains why they are chemically similar?

• Their atoms have one valence electrons.

• Their atoms have more neutrons than protons.

• Their atoms have the same number of energy levels.

• Their atoms contain equal numbers of protons and electrons.

Atoms of which two elements are represented by these models?

• Oxygen, O, and neon, Ne

• Fluorine, F, and neon, Ne

• Silicon, Si and phosphorus, P

• Beryllium, Be, and boron, B

Tags

NGSS.MS-PS1-1

Based on these drawings, which element is the least reactive?

• Neon, because it has two energy levels with eight electrons in the second level

• Chlorine, because it has three energy levels with seven electrons in the third level

• Gallium, because it has four energy levels with three electrons in the fourth level

• Tin, because it has five energy levels with four electrons in the fifth level.

Tags

NGSS.MS-PS1-1

Based on the information in the table, which conclusion about the chemical reactivity of these elements is valid?

• Boron is the most reactive because it has the most protons.

• Fluorine is the most reactive because it has 7 electrons in the outer shell.

• Silicon is the most reactive because it has an equal number of protons and neutrons.

• Gallium is the most reactive because it has many more neutrons than protons.

Tags

NGSS.MS-PS1-1

Which student's responses are correct?

• Student 1

• Student 2

• Student 3

• Student 4

Tags

NGSS.MS-PS1-1

A chemist is identifying the elements present in a sample of seawater. What characteristics of an element's atoms always determines the element's identity?

• The number of protons

• The number of neutrons

• The location of valence electrons

• The number of valence electrons

An atom of which element is represented by this model?

• Boron (B)

• Carbon (C)

• Neon ( Ne)

• Sodium (Na)

Tags

NGSS.MS-PS1-1

Which of the following characteristics is similar for fluorine and iodine?

• Number of Protons

• Number of Neutrons

• Number of Orbitals

• Number of Valence Electrons

The valence electrons model shown is used by middle school students to help master the concept of determining the number of valence electrons for an element. Each student is provided with a different element card and bingo chips to map the electron configuration of an element. Where are valence electrons located on the model?

• Near the nucleus

• In the middle of the atom

• At the innermost level

• At the outermost level

Tags

NGSS.MS-PS1-1