Do i still have a chance to get into an Ivy league or Oxford and Cambridge with mediocre first year grades?

Probably not. What is your overall GPA? Also: do you have anything interesting about your profile that may help offset your poor grades? (publications, work experience, winning an Olympic medal... those kinds of things.)

Im studying in the UK so we dont have a gpa system however my grades are 62 in 1 subject which is the highest in the class of about 60 i believe. Two fifties ( i dont remember exactly but they are between 50-60) and 1 pass. I do have work experience and i have published articles and have done loads of volunteer work and am also a TA for one of my lecturers.
In my uni, only 1 grade from 1st year is counted towards final degree classification and i still have 2 more years. If i get good grades (1st class or a 2.1) will i than have a chance of getting in?