Radiation, Radioactivity, Half life

An atom has a mass number of 208 and an atomic number of 82. What would be the approximate proton-to-neutron (p:n) ratio for this element, and would it likely be stable?

• 1:1, stable

• 1:1.5, unstable

• 1:1.5, stable

• 1:1, unstable

An isotope of Radium (Ra) has an atomic number of 88 and a mass number of 226. If this isotope undergoes alpha decay, what will be the atomic number and mass number of the resulting daughter nucleus?

• Atomic number 86, mass number 222

• Atomic number 88, mass number 222

• Atomic number 90, mass number 230

• Atomic number 84, mass number 222

What is the primary reason an unstable atomic nucleus undergoes radioactive decay?

• To increase its proton-to-neutron ratio to 1:1

• To become a heavier, more stable nucleus

• To emit light and become an isotope

• To move toward a more stable proton-to-neutron ratio

What is the specific composition of an alpha (α) particle?

• A high-energy electron

• A high-energy proton

• A high-energy helium nucleus

• A high-energy gamma ray

An isotope of Lithium (Li) with a mass number of 8 and an atomic number of 3 undergoes beta decay. What are the mass number and atomic number of the resulting nucleus?

• Mass number 8, atomic number 4

• Mass number 8, atomic number 2

• Mass number 7, atomic number 4

• Mass number 7, atomic number 2

Which type of radiation has the highest penetrating power?

• Alpha particles

• Beta particles

• Gamma rays

• Positrons

A sample of a radioisotope starts with a mass of 160 g. After 4 half-lives, how many grams of the radioisotope will remain?

• 80 g

• 40 g

• 20 g

• 10 g

In an electric field, what direction would beta particles deflect and why?

• Towards the positive plate because they are positively charged.

• Towards the negative plate because they are negatively charged.

• Towards the positive plate because they are negatively charged.

• They would not deflect because they have no charge.

What is the atomic number change in a parent atom after it undergoes positron decay?

• It decreases by 1.

• It increases by 1.

• It decreases by 2.

• It remains unchanged.

What happens to the mass number of a nucleus during beta decay?

• It decreases by 4.

• It increases by 1.

• It remains unchanged.

• It decreases by 1.