Problem with beamer xcolor and cellcolor

Question

I'm having trouble changing the cellcolor in beamer. I've loaded xcolor alongside beamer, and specified the svgnames and table options;

\documentclass[xcolor=svgnames,smaller,12pt,table]{beamer}

Here's how I try to change the cellcolor in beamer;

\begin{table}[H]
\centering
\caption{Summary of the differences between open and cloed word classes}

\rowcolors{2}{white}{pink!30}
\begin{tabular}{>{\centering\arraybackslash}p{5cm}>{\centering\arraybackslash}p{5cm}}
Open-class & Closed-class\\ 
\hline
\cellcolor[yellow]{0.5}Admit new members & Do not admit new members \\ 
Are numerous & Are few \\ 
Express "content" & Do not express "content" \\ 
Carry stress & Rarely carry stress \\ 
Can be long, e.g. \textit{antidisestablishmentarianism} & Tend to be short, e.g. \textit{the, on} \\
\hline
\end{tabular} 
\end{table}

I get the error message undefined color model. I checked whether yellow is an SVG color and it is. I also defined a color model called yellow, and this didn't work either.

Answer 1

\cellcolor{yellow!50}

is a correct syntax. I suppose you mean a gray color. Then it is

\cellcolor[gray]{0.5}

gray is the color model