Charge carrier that forms a bond within each of this puzzle's four longest answers

Question:

Answer:

ION

Length:

Similar Crossword Questions:

Ones in charge of a case ... or a literal hint to the eight other longest answers in this puzzle
Pentecost, e.g., and what can literally be found in this puzzle's four other longest answers
Where to find the first words of the four longest puzzle answers
Siesta taken by this puzzle's longest answers
Newsstand buy, for shortÂ—one begins each of the four longest puzzle answers (and also ends the last one)
Game that can follow the first part of this puzzle's four longest answers
Word divided in this puzzle's nine longest answers
Stocking stuffer found in seven of this puzzle's longest answers
They're hidden in this puzzle's seven longest answers
Some graffiti signatures (which were used to form this puzzle's four longest answers)
Big fight, and clue to this puzzle's theme that begins the four longest answers
"Figure head" found in this puzzle's longest answers
AprÃ¨s-___ (following a day on the slopes -- and, literally, where the first words of the four longest puzzle answers can be found)
Busy one that has made its mark in this puzzle's five longest answers
Geeky sort found within this puzzle's four longest answers
Pet targeted by the first words of this puzzle's four longest answers
The starts of this puzzle's six longest answers are types of them
European acme, and word hiding in this puzzle's 5 longest answers
It precedes the last words of the four longest puzzle answers
Important trial figure, or what you'll be when you read this puzzle's other four longest answers
Words to a kidder, and a hint to how this puzzle's five longest answers were created
Final (and a word that can precede the first word of this puzzle's longest answers)
Annual cause of losing an hr.'s sleep hidden in this puzzle's 10 longest answers
"Dog the Bounty Hunter" network, and a hint to the theme in this puzzle's four longest answers
Bird hiding in the four longest puzzle answers