Isotopes of an element have:

The same number of protons but different numbers of neutrons

Half-life is defined as the time for:

Half the nuclei in a sample to decay

Use tongs and keep it at a distance

You cannot predict exactly when a given nucleus will decay

12questions. Pick an answer and you'll see why right away.

The nucleus of an atom contains:
The proton number of an atom tells you:
An atom is written as $^{23}_{11}\text{Na}$ . How many neutrons does it have?
Isotopes of an element have:
Which radiation is a helium nucleus with a charge of $+2$ ?
Which radiation is the most penetrating?
Beta radiation is stopped by:
Half-life is defined as the time for:
A source has a half-life of $5\ \text{days}$ and a count rate of $800$ counts per minute. What is the count rate after $10\ \text{days}$ ?
After three half-lives, a radioactive sample falls to what fraction of its starting amount?
Which is a safe way to handle a radioactive source?
Radioactive decay is described as a random process because: