A 16-year-old boy was arrested Thursday in last week’s shooting of a mother and wife, shot in the face during an apparent botched robbery in her Chinatown building. Police said the teen was picked up more than a week after the Sept. 9 shooting on Market Street where Ying Zhu Liu, 57, was killed. Charges are expected to include murder, robbery, burglary and criminal possession of a weapon. According to the investigation, Liu’s husband was in a building elevator with two men around 11 p.m. When he got out, they did too — and tried to rob him. Liu walked into the hallway after hearing the commotion and took a bullet to the head. Police said both suspects fled on foot. One was described as wearing a black ski mask and a half-red, half-black hooded jacket with white sneakers. The other had on a black ski mask, black hooded jacket and black pants, police said.