how to get third element of class in jquery code example

Example 1: jquery specific child by index

<div class="second">
    <div class="selector" id="selFirst">Number One</div>
    <div class="selector" id="selSecond">Number Two</div>
    <div></div>
</div> 
<script>
	var index = 0
 	console.log($('.second').children().eq(index).text());
 	//Number One
</script>

Example 2: select 2nd td jquery

$(".location table tbody tr td:first-child").addClass("black");
$(".location table tbody tr td:nth-child(2)").addClass("black");