Chapter U1.11, Problem 4E

Interpretation Introduction

Interpretation:

The particles that will be attracted to a negative charge are to be identified and explained.

Concept introduction:

An atom is made of many sub - atomic particles. It has a nucleus made of protons and neutrons, and electrons revolving around the nucleus. The protons are positively charged particles, electrons are negatively charged particles and neutrons do not have any charge.

Answer to Problem 4E

The following particles will be attracted to a negative charge:

• A proton
• A nucleus

Since electrons are negatively charged, they will be repelled by another negative charge. The protons are positively charged particles, so they will be attracted by a negative charge. A neutron is an electrically neutral particle, so it will not be attracted by a negative charge. A nucleus has protons and neutrons, so it has net positive charge. Hence nucleus will be attracted by a negative charge. An atom has no charge so it will not be attracted by a negative charge.

Explanation of Solution

Given information:

Positive and negative charges are attracted to one another.

According to Rutherford’s model of atom, most of atom’s mass was concentrated in the center of the atom which consisted of nucleus. The nucleus was a collection of positively charged particles called protons. The electrons circled around the nucleus. Most of the atom was an empty space.

Bohr’s model is a planetary model in which electrons orbit a small positively charged nucleus just as planets orbit the Sun.

• Electrons are subatomic particles with a negative charge. Like charges repel and unlike charges attract. So an electron will not be attracted by a negative charge. Rather it will be opposed by a negative charge.
• Protons are subatomic particles with positive charge. Like charges repel and unlike charges attract. So a proton will be attracted by a negative charge.
• Neutrons are subatomic particles without any charge. That is, they are neutral. Like charges repel and unlike charges attract. So a neutron will not be attracted by a negative charge.
• A nucleus is made of protons and neutrons. Since protons have positive charge and neutrons are neutral, the nucleus has a net positive charge. So it will be attracted by a negative charge as opposite charges attract.
• An atom consists of negatively charged electrons and positively charged nucleus. A neutral atom has equal number of negative charges and positive charges. In other words, the positive charge on a proton is equal in magnitude to the negative charge on an electron. So an atom does not have any charge. Hence it will not be attracted by a negative charge.

Conclusion

Positive and negative charges are attracted to one another. Only protons and nucleus will be attracted by a negative charge because they have positive charges.