WASHINGTON — On the fourth floor of the Eisenhower Executive Office Building, the staff of the White House chief technology officer has been virtually deleted, down from 24 members before the election to, by Friday, only one.

Scores of departures by scientists and Silicon Valley technology experts who advised President Trump’s predecessor have all but wiped out the larger White House Office of Science and Technology Policy.

Mr. Trump has not yet named his top advisers on technology or science, and so far, has made just one hire: Michael Kratsios, the former chief of staff for Peter Thiel, the Silicon Valley investor and one of the president’s wealthiest supporters, as the deputy chief technology officer.

Neither Mr. Kratsios, who has a bachelor’s degree in political science from Princeton, nor anyone else still working in the science and technology office regularly participates in Mr. Trump’s daily briefings, as they did for President Barack Obama.