These elements, unlike the transition elements, do not exhibit variable oxidation states, and their valence electrons are only present in their outer shell. All of these elements are solid, have a relatively high density, and are opaque. They have oxidation numbers of +3, Â±4, and -3. The Other Metals are: Aluminum Gallium Indium Tin Thallium Lead Bismuth This website is copyright Â© 1996-2012 Yinon Bentor. The 7 elements classified as other metals are located in groups 13, 14, and 15.
1 The embryo grows rapidly, and the baby's external features begin to form. 2  Your baby's brain, spinal cord, and heart begin to develop. 3  Baby's gastrointestinal tract starts to form.  It is during this time in the first trimester that the baby is most at risk for damage from things that may cause birth defects.
During the fetal stage, which runs from the 11th week until birth, your baby will grow longer and gain weight fast, and organs and body parts will continue to develop. The last 2 weeks of the first trimester are the beginning of the fetal stage. This is one of the first things to develop during the embryonic stage. 2  This means your babyâs brain, spinal cord and nerves form during this stage. 3  Heart. 4  An S-shaped tube forms on the front of the embryo.