[Tex/LaTex] Using `pause` in the right way

Question

When i compile to pdf, \pause is supposed to work making items appear once at a time, isn't it? If it is so, it is not working for me, maybe is an error in the way i am using it.
I just want the "items" appear once at a time.
I post only a part of the code.

\subsection{Química y tecnología}
\begin{frame}[allowframebreaks]{Química y tecnología}
\vspace{-1cm}
\begin{itemize}  %cosas que quiero que aparezcan de a una
    \item
First item\pause \\~\\
        \item 
  Second item\pause \\~\\
        \item 
  Last item \pause
    \end{itemize}
\end{frame}

Packages i am using are the following:

\documentclass[aspectratio=169, hyperref={pdfpagelabels=false}]{beamer}
%\documentclass[handout, hyperref={pdfpagelabels=false}]{beamer}
\usetheme{Madrid} 
\let\Tiny=\tiny
\usepackage{multimedia}
\usecolortheme{whale} 
\usepackage[utf8]{inputenc}
\usepackage[spanish]{babel}
\usefonttheme{professionalfonts}  
\usenavigationsymbolstemplate{} 
\setbeamertemplate{footline}[frame number]
\setbeamertemplate{frametitle}[default][center]
\setbeamersize{text margin left=2em,text margin right=2em}
\usepackage[export]{adjustbox}
\usepackage{graphicx}
\usepackage{chemfig} 
\usepackage{tikz}
\usetikzlibrary{shapes,arrows}
\usepackage{ragged2e}

I didnt post a MWE because i am quite sure i am using pause in a wrong way, but i can not see it.

Answer 1

\pause is supposed to show an item, followed by another one (still keeping the first) and so on. That's equivalent to the option <+-> for itemize.

Btw: If you keep allowframebreaks because of that, you can remove it, because \pause will work without.

To show an item once at a time use <1> as specifier for items where 1 is the number of the frame you want it to appear in. Another version is to use the global <+>.

\documentclass{beamer}

\begin{document}
\begin{frame}{Test}
\vspace{-1cm}
\begin{itemize}[<+>]  %cosas que quiero que aparezcan de a una
    \item First item
    \item Second item
    \item Last item
\end{itemize}
\end{frame}
\end{document}