Sam Lee is an ambitious hawker turned entrepreneur who is looking to expand his food court business. He has been buying up small coffee shops around Singapore, especially from elderly owners who are getting ready to retire and wish to sell their business for a profit. Sam met with Uncle Peng, his father's brother, who was the owner of a small coffee shop called "PENG PENG" in the northern part of Singapore. Uncle Peng was getting on in years and lamented that his children did not want to take over the business. He told Sam that he wanted to sell his coffee shop business so he could retire and travel around the world. He further said that his coffee shop was recently valued at $3 million. Sam was excited at the idea and made an offer of $3 million on the spot to Uncle Peng. Uncle Peng was surprised and asked Sam if there were any terms that they needed to finalise. Sam replied by saying, "We are family and we should trust each other. We don't need to spend money on lawyers to complicate matters with so many terms." However, Sam tried to address Uncle Peng's concerns by scribbling on a piece of paper the following statement: "Uncle Peng will sell his coffee shop (PENG PENG), located at 2 Lorong Chuan, to Sam for $3 million, subject to final terms (if any) being agreed within 1 week." Sam proceeded to sign on the piece of paper, before offering it to Uncle Peng to sign. Uncle Peng also signed on the piece of paper. Sam and Uncle Peng also shook hands. The next day, Uncle Peng announced to all his employees, customers and suppliers that he had sold PENG to Sam and they should immediately start dealing with Sam. Sam also started to liquidate some of his stock investments in order to raise funds to finance the purchase of the coffee shop. However, when Uncle Peng turned up at Sam's office two days later to execute the formal paperwork, Sam told Uncle Peng that he no longer wanted to buy the business.

Explain whether there is a valid contract between Sam and Uncle Peng. In your answer, you should identify and discuss the four (4) elements of a contract.