If I say: "one day, a bridge will be built over that river"
DOes it mean the construction will only take one day?
In any case, Chapter 1 of Genesis was added well after the original Hebrew creation myth (what we now call Genesis 2). It was originally a Babylonian myth about seven gods who, being bored, decided to create a world. Each god had a turn. When the 7th god's turn came, there was nothing to add, so he "rested".
For a monotheist religion, the gods were changed to days, in order to emphasise the observance of the Sabbath (the rest on the 7th day). In the original texts (or, at least, those much older than "The Bible"), the words and grammatical structure show that the first chapter is newer than the second chapter.
The Big Bang theory started off as the idea (and mathematical model) of a priest. When a theory, based on the priest's work, was published in 1948, a famous atheist (and famous astrophysicist) was so much against the idea of the universe having possibly being created, that he came up with another theory (Steady State) where the universe does not need a beginning (therefore, no creation). That theory came out in 1949; it is during a radio interview about his theory that the atheist came up with the awful nickname "Big Bang".
Very few scientists (whether they be religious or not) dismiss the Big Bang theory. Outside the USA, very few "religious people" dismiss it. In the USA, it does clash with some of the recent so-called Christian beliefs (for example, young Earth). These people have been deceived... but in the wrong direction.