I find Nolo a great resource for basic legal questions although always check with a tax pro, CPA or attorney, to make certain your situation is as you believe it to be.
Here is an interesting point of which I was not aware from the Nolo article.
"If your spouse dies and you subsequently sell your home, you qualify for the $500,000 exclusion if the sale occurs within two years after the date of death and the other requirements discussed above were met immediately before the date of death."
The $250,000/$500,000 Home Sale Tax Exclusion | Nolo