App for allowing the user to type in chemistry formulas using a custom keyboard
You can use some if else statement, where u use several independent ifs. This will lead to a slightly faster code, because in the case, where the previous if is try, no further testing is needed. Personally I also find it more readable for short and medium sized code block. 

if (![currentElement isEqualToString:lastElementPressed])  {
    //…
} else { 
    if (consecutiveElementCount == 1) { 
         //…
    } else if (consecutiveElementCount &gt; 1) {
        //…
    } 
    if (consecutiveElementCount &lt; 11) {
        //…
    }
}


But beside that, I don't think, that you are using to many if-statements. But you should use proper indention, as it will build visual block of your code and helps you, to understand the structure.

There is a rule of thumb: If a method/function does not fit on your screen, it becomes to long, and you should use well-named helper functions to break it into several logical blocks.