Explore BrainMass
Share

Atomic theory of matter

This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

Please see attachment

Question 27
The atomic and mass numbers for four different atoms are given below. Which two are isotopes of the same element?

Atom Atomic Number Mass Number
A 100 257
B 101 257
C 101 260
D 102 259
A and B
B and C
B and D
C and D

Question 30
Describe at least two experiments, including the observed results, that caused the scientific community to accept changes to Dalton's original model of the atom.

Question 31
Explain, in your own words, why different elements produce different colors of light when heated.

Question 32
Carbon has an atomic number of 6, but the following orbital notation for carbon is incorrect. Explain the error in terms of the rules for electron arrangements.

© BrainMass Inc. brainmass.com March 22, 2019, 3:27 am ad1c9bdddf
https://brainmass.com/chemistry/general-chemistry/atomic-theory-matter-616342

Attachments

Solution Preview

Chemical element is defined by the number of protons in the nucleus of it atoms. For example, all Carbon atoms have exactly six protons in their nuclei. All Radium atoms have exactly 88 protons in their nuclei.
Since atoms are electrically neutral, the number of protons (positive charge) must be equal to the number of electrons (negative charge) orbiting the nucleus.
The number of protons in the element's atom is the Atomic number.
This number is interchangeable with the name of the element.
However, the nucleus contains neutrons, which have no electric charge. Therefore we can change the number of neutrons in the nucleus without changing the chemical properties of the element. Hence we can have atoms of the same element that have different number of neutrons. Atoms of the same element with different number of neutrons are called isotopes of that element. For example, Carbon-12 nucleus contains 6 protons and 6 neutrons. Carbon-14 contains 6 protons (it is still carbon) but it has 8 neutrons.
Carbon-12 and Carbon-14 are isotopes of carbon.
Since neutron weigh about the same as protons, the sum of the protons and neutrons in the nucleus is the "Mass number".
Isotopes of the same element have the same atomic number (protons only) but different mass number (protons + neutrons).
In our carbon example, both Carbon-12 and Carbon-14 have atomic number of 6, but Carbon-12's mass number is 12 while Carbon-14 mass number is 14.

Question 27
The atomic and mass numbers for four different atoms are given below. Which two are isotopes of the same element?

Atom Atomic Number Mass ...

Solution Summary

The solution answers 4 questions regarding the atomic theory of matter in great detail

$2.19