Ch 3: Chemistry Fundamentals (Princeton Review) Flashcards
What is the mass defect?
the difference between the predicted mass of a nucleus and the actual mass.
What equation relates the energy released when a nucleus is formed to mass?
How can you calculate this?
What does this imply?
E = mc2
multiple the mass defect (m) by speed of light squared. Answer will be given in joules.
Mass can become energy and energy can become mass.
The nuclear strong force (that holds an atom together even though protons repel one another) is (stronger/weaker) than the electrostatic force.
stronger; if it were weaker, the nucleus would naturally break apart
The ______ energy is the energy required to overcome the nuclear strong force in order to separate nucleons.
binding
nucleus (smaller mass) + binding energy = separated nucleons (greater mass)
Breaking an atom into its constituent components must then be an _________ process, because it requires an input of energy. Formation of an atom from its constituent components is an _________ process bc it gives off energy (the binding energy)
endergonic
exergonic
(from AK Lectures: Binding Energy)
If the N:Z ratio is greater than 1, the nucleus is unstable and will undergo radioactive decay.
The strong force acts only over _____ distances.
short
As the atomic number increases, the ideal N:Z ratio increases to about 1.5.
When Z > 83, the electrostatic force (repelling force among protons) is so great that all the nuclei are unstable and will undergo radioactive decay.
In alpha decay, an alpha particle is ejected from an unstable nucleus.
An alpha particle has the same composition as a ______ nucleus: _ nucleons total, _ protons, and _ neutrons.
helium
4, 2, 2
In radioactive decay, both the number of nucleons and the charge is conserved.
In beta decay, an electron is ejected from an unstable nucleus
