Question

1. what is radioactivity?
2. what does it mean for an atom to be radioactive?

match the words in the left column to the appropriate blanks in the sentences on the right. make certain eac

atoms

1. radioactivity is the of

tiny , (to the human
eye) particles by the of certain
molecules
spontaneously

emission

1. a radioactive atom will

nuclei
these particles.
visible
absorb
invisible
emit

Explanation:

To solve the matching:

1. For the first sentence: Radioactivity is the emission (process of releasing) of tiny, invisible (to human eye) particles by the nuclei (central part) of certain atoms (radioactive atoms emit from their nuclei).
2. For the second sentence: A radioactive atom will spontaneously (naturally, without external force) emit (release) these particles.

Answer:

1. Radioactivity is the $\boldsymbol{\text{emission}}$ of $\boldsymbol{\text{tiny}}$, $\boldsymbol{\text{invisible}}$ (to the human eye) particles by the $\boldsymbol{\text{nuclei}}$ of certain $\boldsymbol{\text{atoms}}$.
2. A radioactive atom will $\boldsymbol{\text{spontaneously}}$ $\boldsymbol{\text{emit}}$ these particles.

(Word - to - blank matches: emission, tiny, invisible, nuclei, atoms; spontaneously, emit)