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.
In the last few weeks of the first trimester, the embryo really starts to take shape. The facial structures begin to form and become recognizable. The neural tube, which will form the brain and spinal cord, develops. Little buds emerge and grow into arms and legs. Around week 8, the embryo becomes a fetus. The kidneys, liver, brain, and lungs are all beginning to function. The fingers and toes are separate and the external genitalia are formed. At 12 weeks, the fetus is about three inches long and weighs about one ounce.