Atlantic Richfield Co., the nation's seventh-largest oil company, reported yesterday that its first-quarter earnings rose 76 percent compared to last year.

Of the top dozen oil companies, only Standard Oil of California has yet to report on its performance in the first three months of 1980.

Of the other 11, the jumps in profits ranged from Tenneco's 45 percent and Gulf Oil Corp.'s 56 percent to Occidental Petroleum corp.'s 236 percent. The big three -- Exxon, Mobil and Texaco -- doubled their earnings.

Atlantic Richfield said it earned $426.1 million in the first quarter ($1.98 a share) on revenues of $5.4 billion. Profits in the first quarter last year were $242.2 million (45 cents) on revenues of $3.5 billion.

Union Oil Co. of California, the fifteenth-biggest U.S. Oil company, also reported yesterday a 34 percent increase in first-quarter profits.

Union said its profits rose to $152.9 million ($1.76 a share) from $114.1 million ($1.30) last year. Revenues increased from $1.76 billion to $2.38 billion.

Atlantic Richfield's chairman, Robert O. Anderson, attributed much of the improvement in his company's profitability to increased production of oil from its share of the Prudhoe Bay oil field in Alaska and the higher prices it is bringing now.

Strong copper prices boosted earnings at the company's Anaconda Mining subsidary also, Anderson said.

Union Oil's chairman, Fred L. Hartley, said its improved earnings came from higher prices for crude oil and natural gas, improved profits from chemicals and higher investment tax credits.

Hartley said Union plans to spend more than $1.6 billion on exploration and capital projects in 1980.